diff --git a/.gitignore b/.gitignore
index 91586fc..af431cd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,3 +33,10 @@ Testing/
 # Doxygen output
 doc/doxygen/
 *.dox.tmp
+
+# Downloaded research papers + derived artifacts (regenerable, not tracked)
+papers/*.pdf
+papers/txt/
+papers/mmd/
+papers/facebook/
+papers/figures/
diff --git a/code/include/hyper_ideal_functional.hpp b/code/include/hyper_ideal_functional.hpp
index 8533135..dfae9b4 100644
--- a/code/include/hyper_ideal_functional.hpp
+++ b/code/include/hyper_ideal_functional.hpp
@@ -374,8 +374,8 @@ static FaceAngles compute_face_angles(
 /// Per-face energy contribution U(f) before subtracting the θ·a and Θ·b terms.
 ///
 /// Supported configurations (faithful port of HyperIdealFunctional.java):
-///   * All three vertices hyper-ideal (v?b = true)       → Meyerhoff/Ushijima volume
-///   * Exactly one vertex ideal (v?b = false, other two true) → Kolpakov-Mednykh volume
+///   * All three vertices hyper-ideal (v?b = true)       → Ushijima 2006 volume
+///   * Exactly one vertex ideal (v?b = false, other two true) → Springborn 2008 volume
 ///
 /// NOT supported — faces with two or three ideal vertices.  The Java reference
 /// (HyperIdealFunctional.java lines 222-231) uses an if/else-if chain that
diff --git a/code/include/hyper_ideal_utility.hpp b/code/include/hyper_ideal_utility.hpp
index e8e2c4e..cf2aacd 100644
--- a/code/include/hyper_ideal_utility.hpp
+++ b/code/include/hyper_ideal_utility.hpp
@@ -16,7 +16,8 @@
 namespace conformallab {
 
 /// Volume of a generalized hyperbolic tetrahedron with dihedral
-/// angles `A,…,F` via the Meyerhoff / Ushijima 2006 formula.
+/// angles `A,…,F` via the Ushijima 2006 formula (DOI 10.1007/0-387-29555-0_13,
+/// arxiv math/0309216). Note: sole author is Ushijima; "Meyerhoff" is not an author.
 /// Same as Java `HyperIdealUtility.calculateTetrahedronVolume()`.
 inline double calculateTetrahedronVolume(double A, double B, double C,
                                          double D, double E, double F) {
@@ -77,7 +78,7 @@ inline double calculateTetrahedronVolume(double A, double B, double C,
 }
 
 /// Volume of a hyperideal tetrahedron with one ideal vertex at γ via
-/// the Kolpakov-Mednykh formula (arxiv math/0603097).  Same as Java
+/// the Springborn 2008 formula (arxiv math/0603097).  Same as Java
 /// `HyperIdealUtility.calculateTetrahedronVolumeWithIdealVertexAtGamma()`.
 inline double calculateTetrahedronVolumeWithIdealVertexAtGamma(
     double gamma1, double gamma2, double gamma3,
diff --git a/code/tests/cgal/test_hyper_ideal_functional.cpp b/code/tests/cgal/test_hyper_ideal_functional.cpp
index 4d2e350..f1ae0e0 100644
--- a/code/tests/cgal/test_hyper_ideal_functional.cpp
+++ b/code/tests/cgal/test_hyper_ideal_functional.cpp
@@ -267,7 +267,7 @@ TEST(HyperIdealFunctional, MultiIdealGuard_AllThreeIdealVertices_Throws)
 TEST(HyperIdealFunctional, MultiIdealGuard_ExactlyOneIdeal_DoesNotThrow)
 {
     // Exactly one ideal vertex per face must NOT throw — it is the supported
-    // one-ideal-vertex configuration (Kolpakov-Mednykh formula).
+    // one-ideal-vertex configuration (Springborn 2008 formula).
     auto mesh = make_triangle();
     auto maps = setup_hyper_ideal_maps(mesh);
 
diff --git a/doc/api/tests.md b/doc/api/tests.md
index 2b10b48..b0b3103 100644
--- a/doc/api/tests.md
+++ b/doc/api/tests.md
@@ -7,7 +7,7 @@ Pure-math tests, only Eigen required. Covers Java utilities ported in Phase 1–
 | File | What it tests |
 |---|---|
 | `test_clausen.cpp` | Clausen Cl₂, Lobachevsky Л, ImLi₂ — values at known points |
-| `test_hyper_ideal_utility.cpp` | Tetrahedron volumes (Meyerhoff / Kolpakov–Mednykh) + Java golden-value oracle (Clausen/Л/ImLi₂, ζ₁₃/₁₄/₁₅/ζ, both volume formulas) |
+| `test_hyper_ideal_utility.cpp` | Tetrahedron volumes (Ushijima 2006 / Springborn 2008) + Java golden-value oracle (Clausen/Л/ImLi₂, ζ₁₃/₁₄/₁₅/ζ, both volume formulas) |
 | `test_matrix_utility.cpp` | Matrix helpers |
 | `test_surface_curve_utility.cpp` | Surface curve utilities |
 | `test_discrete_elliptic_utility.cpp` | Discrete elliptic functions |
diff --git a/doc/architecture/project-structure.md b/doc/architecture/project-structure.md
index ab893dd..5d4c9a8 100644
--- a/doc/architecture/project-structure.md
+++ b/doc/architecture/project-structure.md
@@ -14,7 +14,7 @@ ConformalLabpp/
 │   │   ├── constants.hpp             # conformallab::PI, TWO_PI
 │   │   ├── clausen.hpp               # Cl₂, Lobachevsky Л, ImLi₂
 │   │   ├── hyper_ideal_geometry.hpp  # ζ₁₃/₁₄/₁₅, lᵢⱼ, αᵢⱼ, σᵢ, σᵢⱼ
-│   │   ├── hyper_ideal_utility.hpp   # Tetrahedron volumes (Meyerhoff / Kolpakov–Mednykh)
+│   │   ├── hyper_ideal_utility.hpp   # Tetrahedron volumes (Ushijima 2006 / Springborn 2008)
 │   │   ├── hyper_ideal_visualization_utility.hpp  # Poincaré disk projection, circumcircle helpers
 │   │   ├── hyper_ideal_functional.hpp # HyperIdeal energy + gradient on ConformalMesh
 │   │   ├── hyper_ideal_hessian.hpp   # HyperIdeal Hessian (symmetric FD, Phase 9b: analytic)
diff --git a/doc/math/references.md b/doc/math/references.md
index ce90980..0a2e522 100644
--- a/doc/math/references.md
+++ b/doc/math/references.md
@@ -29,11 +29,11 @@ Java reference implementation: [github.com/varylab/conformallab](https://github.
 | Reference | Used in |
 |---|---|
 | ✅ **Springborn** — *Ideal Hyperbolic Polyhedra and Discrete Uniformization*, Discrete & Computational Geometry **64** (2020), pp. 63–108. DOI: [10.1007/s00454-019-00132-8](https://doi.org/10.1007/s00454-019-00132-8) | `hyper_ideal_geometry.hpp` — ζ₁₃/ζ₁₄/ζ₁₅ functions; `hyper_ideal_functional.hpp` |
-| ✅ **Kolpakov, Mednykh** — *A Formula for the Volume of a Hyperbolic Tetrahedron*, arXiv: [math/0603097](https://arxiv.org/abs/math/0603097) (2006) | Tetrahedron volume with one ideal vertex: `calculateTetrahedronVolumeWithIdealVertexAtGamma` in `hyper_ideal_utility.hpp` (Phase 9b analytic Hessian) |
-| ✅ **Meyerhoff, Ushijima** — *A Note on the Dirichlet Domain*, in: The Epstein Birthday Schrift (2006) | Tetrahedron volume with three ideal vertices: `calculateTetrahedronVolumeFullyIdeal` in `hyper_ideal_utility.hpp` |
-| **Pinkall, Polthier** — *Computing Discrete Minimal Surfaces and Their Conjugates*, Experimental Mathematics (1993) | `euclidean_hessian.hpp` — cotangent Laplacian |
-| **Bobenko, Springborn** — *Variational Principles for Circle Patterns and Koebe's Theorem*, Transactions AMS (2004) | Variational angle-sum framework underlying all three functionals |
-| **Luo** — *Combinatorial Yamabe Flow on Surfaces*, Communications in Contemporary Mathematics (2004) | Inversive-distance functional — **new research** in Phase 9a.2 (no Java original; implemented from this paper + Glickenstein 2011 + Bowers-Stephenson 2004) |
+| ✅ **Springborn** — *A variational principle for weighted Delaunay triangulations and hyperideal polyhedra*, J. Differential Geometry **78**(2) (2008), pp. 333–367. arXiv: [math/0603097](https://arxiv.org/abs/math/0603097) | Tetrahedron volume with one ideal vertex: `calculateTetrahedronVolumeWithIdealVertexAtGamma` in `hyper_ideal_utility.hpp` (Phase 9b analytic Hessian). ⚠️ *Korrektur:* war fälschlich als „Kolpakov–Mednykh 2006" zitiert — dieses Autorenpaar hat 2006 kein gemeinsames Paper veröffentlicht. Die Java-Quelle verlinkt korrekt auf math/0603097 (= Springborn 2008); der falsche Autorenname wurde beim C++-Port hinzugefügt.* |
+| ✅ **Ushijima** — *A Volume Formula for Generalised Hyperbolic Tetrahedra*, in: Prékopa, Molnár (eds.) *Non-Euclidean Geometries*, Mathematics and Its Applications vol. 581, Springer 2006. DOI: [10.1007/0-387-29555-0_13](https://doi.org/10.1007/0-387-29555-0_13). arXiv: [math/0309216](https://arxiv.org/abs/math/0309216) (2003) | Tetrahedron volume with three ideal vertices: `calculateTetrahedronVolumeFullyIdeal` in `hyper_ideal_utility.hpp`. ⚠️ *Korrektur:* war fälschlich als „Meyerhoff, Ushijima — A Note on the Dirichlet Domain — The Epstein Birthday Schrift" zitiert. Meyerhoff ist kein Autor; Titel und Buch waren beide falsch. Die Java-Quelle verlinkt korrekt auf DOI 10.1007/0-387-29555-0_13 ohne Autorennamen. |
+| **Pinkall, Polthier** — *Computing Discrete Minimal Surfaces and Their Conjugates*, Experimental Mathematics **2**(1), pp. 15–36 (1993). DOI: [10.1080/10586458.1993.10504266](https://doi.org/10.1080/10586458.1993.10504266) | `euclidean_hessian.hpp` — cotangent Laplacian |
+| **Bobenko, Springborn** — *Variational Principles for Circle Patterns and Koebe's Theorem*, Trans. Amer. Math. Soc. **356**(2), pp. 659–689 (2004). arXiv: [math/0203250](https://arxiv.org/abs/math/0203250) | Variational angle-sum framework underlying all three functionals |
+| **Luo** — *Combinatorial Yamabe Flow on Surfaces*, Commun. Contemp. Math. **6**(5), pp. 765–780 (2004). DOI: [10.1142/S0219199704001501](https://doi.org/10.1142/S0219199704001501). arXiv: [math/0306167](https://arxiv.org/abs/math/0306167) | Inversive-distance functional — **new research** in Phase 9a.2 (no Java original; implemented from this paper + Glickenstein 2011 + Bowers-Stephenson 2004) |
 | **Bowers, Stephenson** — *Uniformizing dessins and Belyĭ maps via circle packing*, Memoirs of the AMS 170(805) (2004) | Introduces **inversive-distance circle packings** (used in Phase 9a.2). *Hinweis:* die zur Initialisierung benutzte Formel I_ij = (ℓ²−r_i²−r_j²)/(2 r_i r_j) ist die **klassische** inversive Distanz (vgl. Glickenstein §5.2: ℓ²=r_i²+r_j²+2r_ir_jη), nicht eine eigene „Bowers-Stephenson-Identität" — B–S liefern die Packungstheorie, nicht diese Formel. |
 | **Glickenstein** — *Discrete conformal variations and scalar curvature on piecewise flat two- and three-dimensional manifolds*, J. Differential Geometry **87**(2) (2011), pp. 201–238 | Analytic Hessian of the inversive-distance functional. ⚠️ *Korrektur:* die Arbeit nummeriert Gleichungen **nicht** im Format „(4.6)" — der Verweis ist durch die **§5.2**-Parametrisierung ℓ²_ij = r²_i + r²_j + 2 r_i r_j η_ij zu ersetzen. Cross-correspondence: η_ij ist die inversive Distanz und entspricht dem Kosinus des **Supplements** des Schnittwinkels (Schnitt bei arccos(−η_ij)) — also I_ij = cos θ_e **nur bis aufs Vorzeichen/Supplement**, nicht wörtlich. |
 | ✅ **Bobenko, Pinkall, Springborn** — *Discrete conformal maps and ideal hyperbolic polyhedra*, Geometry & Topology **19**(4) (2015), pp. 2155–2215. arXiv: [1005.2698](https://arxiv.org/abs/1005.2698) (first posted 2010) | Face-based circle-packing functional (`CPEuclideanFunctional.java` → `cp_euclidean_functional.hpp`, Phase 9a.1) |
@@ -79,10 +79,10 @@ builds on this paper and augments it with Ptolemaic flips.
 |---|---|
 | **Farkas, Kra** — *Riemann Surfaces*, Springer GTM 71 | Siegel period matrix, Teichmüller theory |
 | **Siegel** — *Topics in Complex Function Theory, Vol. 2*, Wiley | Siegel upper half-space H_g, Sp(2g,ℤ) reduction |
-| **Bobenko, Mercat, Schmies** — *Period Matrices of Polyhedral Surfaces*, in: Computational Approach to Riemann Surfaces (2011) | Discrete period matrices on polyhedral surfaces |
+| **Bobenko, Mercat, Schmies** — *Conformal Structures and Period Matrices of Polyhedral Surfaces*, in: Bobenko, Klein (eds.) *Computational Approach to Riemann Surfaces*, Lecture Notes in Mathematics vol. 2013, Springer 2011, pp. 213–226. DOI: [10.1007/978-3-642-17413-1_7](https://doi.org/10.1007/978-3-642-17413-1_7) | Discrete period matrices on polyhedral surfaces |
 | **Bobenko, Bücking** — *Convergence of discrete period matrices and discrete holomorphic integrals for ramified coverings of the Riemann sphere*, Math. Phys. Anal. Geom. **24**, Art. 23 (2021). DOI: [10.1007/s11040-021-09394-2](https://doi.org/10.1007/s11040-021-09394-2) | Phase 10b: discrete Siegel period matrix Ωᵢⱼ from cotangent-weighted integration **plus** the convergence result Ω_discrete → Ω_smooth under refinement (für ramified coverings) — belegt die Diskret-zu-glatt-Aussage in `novelty-statement.md §3.3. |
 | **Rivin, Schlenker** — *The Schläfli formula in Einstein manifolds with boundary*, Electron. Res. Announc. AMS **5** (1999), pp. 18–23 | Phase 9b-analytic: modern form of the Schläfli identity `2 dV = Σ aₑ dαₑ` for manifolds with boundary — the bilinear form used to derive the analytic HyperIdeal Hessian. |
 | **Pinkall, Springborn** — *A discrete version of Liouville's theorem on conformal maps*, Geometriae Dedicata **214** (2021), pp. 389–398. arXiv: [1911.00966](https://arxiv.org/abs/1911.00966) | Phase 10b uniqueness: proves that the discrete conformal structure (and hence Ω) is a conformal invariant — the discrete Liouville theorem. Justifies that conformallab++ outputs a canonical representative. |
-| **Born, Bücking, Springborn** — *Quasiconformal distortion of projective transformations and discrete conformal maps*, arXiv: [1505.01341](https://arxiv.org/abs/1505.01341) (2015) | Phase 10c error analysis: quantifies how well the discrete H²/Γ embedding approximates the smooth hyperbolic metric; error bounds for the Fuchsian group representation. |
-| **Knöppel, Crane, Pinkall, Schröder** — *Stripe Patterns on Surfaces*, ACM SIGGRAPH (2015). DOI: [10.1145/2766890](https://doi.org/10.1145/2766890) | Phase 10a cross-validation: applies discrete holomorphic 1-forms to direction field design; geometry-central provides an independent C++ implementation to cross-check the Phase 10a `DiscreteHolomorphicFormUtility` port. |
+| **Born, Bücking, Springborn** — *Quasiconformal distortion of projective transformations and discrete conformal maps*, Discrete & Computational Geometry **57**(2), pp. 305–317 (2017). DOI: [10.1007/s00454-016-9854-7](https://doi.org/10.1007/s00454-016-9854-7). arXiv: [1505.01341](https://arxiv.org/abs/1505.01341) (preprint 2015) | Phase 10c error analysis: quantifies how well the discrete H²/Γ embedding approximates the smooth hyperbolic metric; error bounds for the Fuchsian group representation. |
+| **Knöppel, Crane, Pinkall, Schröder** — *Stripe Patterns on Surfaces*, ACM Transactions on Graphics **34**(4), Article 39 (SIGGRAPH 2015). DOI: [10.1145/2767000](https://doi.org/10.1145/2767000). ⚠️ *Kein arXiv-Preprint* (arXiv:1502.06686 ist ein anderes Paper — Data-Driven Shape Analysis — und wurde aus dem papers/-Ordner entfernt). | Phase 10a cross-validation: applies discrete holomorphic 1-forms to direction field design; geometry-central provides an independent C++ implementation to cross-check the Phase 10a `DiscreteHolomorphicFormUtility` port. |
 | **Sawhney, Crane** — *Boundary First Flattening*, ACM TOG **37**(1), Article 5 (2017). DOI: [10.1145/3132705](https://doi.org/10.1145/3132705) | Complementary method to Phase 9d: boundary-prescribed conformal flattening — user specifies boundary shape, interior conforms freely. Contrast: conformallab++ prescribes cone angles in the interior; BFF prescribes the boundary. Alternative approach for applications needing controlled boundary. |
diff --git a/doc/reviewer/finding-orchestration.md b/doc/reviewer/finding-orchestration.md
index be1de3f..b1d9523 100644
--- a/doc/reviewer/finding-orchestration.md
+++ b/doc/reviewer/finding-orchestration.md
@@ -59,7 +59,7 @@ Status: ✅ done · ⬜ open (actionable) · ⏸ deferred (intentional) · ⛔ b
 | V3 | input-val | 🟡 | ✅ | Sonnet | S1 |
 | C1 | test-cov | 🔴 | ✅ | Sonnet | S1 |
 | N4, N6 | numerics | 🟡/🔵 | ✅ | Haiku | S1 |
-| M1, M2, M4 | math-cite | 🟡/🔵 | ✅ | Haiku | S1 |
+| M1, M2, M4 | math-cite | 🟡/🔵 | ✅⚠️ | Haiku → re-fix 2026-06-04 | S1 + nachkorrigiert |
 | C2, C3 | test-cov | 🔴 | ✅ | Sonnet | S1 |
 | V1, V2, V4 | input-val | 🟡 | ✅ | Sonnet | S1 |
 | I2, I3, I4 | test-cov | 🟡 | ✅ | Sonnet | S1 |
@@ -162,6 +162,42 @@ Gated by the author's reply on porting/relicensing rights.
 ### 👤 Out of model scope
 - **M5** — the large hand-derivations need a domain-expert prose review
   (the numerical results are already validated; the prose is not).
+- **Alle Zitationen** — alle `references.md`-Einträge müssen von einem
+  Fachexperten manuell verifiziert werden (siehe Lektion unten).
+
+---
+
+## ⚠️ Lektion: KI-gestützte Citation-Audits können Fehler einführen
+
+**Datum:** 2026-06-04  
+**Befund:** Die M1-Auflösung in S1 (Haiku, 2026-05-31) war selbst fehlerhaft:
+
+- Der Haiku-Audit erkannte korrekt, dass `Kolpakov–Mednykh` in `references.md` fehlt
+- Als „Fix" wurde die Zeile mit arXiv:math/0603097 ergänzt — aber **math/0603097 ist Springborn 2008**, nicht Kolpakov–Mednykh
+- Das Autorenpaar „Kolpakov & Mednykh" hat **2006 kein gemeinsames Paper veröffentlicht** (früheste Zusammenarbeit: 2010, über Torusknoten, nicht Tetraedervolumen)
+- Der falsche Autorenname entstand bereits beim Java→C++-Port; der Audit hat ihn zementiert statt korrigiert
+
+**Nachkorrektur:** 2026-06-04, 7 Dateien korrigiert (Code-Kommentare, references.md, roadmap, architecture-doc, tests-doc, audit-doc).
+
+**Konsequenz für das Projekt:**
+
+> KI-Modelle können bei Citation-Audits plausibel klingende aber falsche  
+> Autoren/Jahres-Zuordnungen produzieren — besonders wenn die Primärquelle  
+> (Java-Code) nur einen Link ohne Autorennamen enthält.
+
+**Empfehlung:**
+
+Vor jeder öffentlichen Veröffentlichung / CGAL-Submission müssen **alle** Einträge
+in `references.md` von einem **Fachexperten (Mensch)** gegen die tatsächlichen
+Papiere verifiziert werden:
+
+| Priorität | Was prüfen |
+|---|---|
+| 🔴 Hoch | Formeln in Code-Kommentaren (`hyper_ideal_utility.hpp`, `hyper_ideal_functional.hpp`) gegen die zitierten Paper |
+| 🔴 Hoch | Ushijima 2006 (DOI 10.1007/0-387-29555-0_13) — arXiv math/0309216 — korrigiert: kein Meyerhoff, anderer Titel, anderes Buch |
+| 🟡 Mittel | Ob Springborn 2008 (math/0603097) die 12-Term-Lobachevsky-Formel tatsächlich enthält |
+| 🟡 Mittel | M3: post-2023 / arXiv-only Zitationen (Bowers-Bowers-Lutz 2026 etc.) |
+| 🔵 Niedrig | Alle weiteren `references.md`-Einträge auf Titel/Jahr/DOI-Konsistenz |
 
 ---
 
diff --git a/doc/reviewer/math-derivation-citation-audit-2026-05-31.md b/doc/reviewer/math-derivation-citation-audit-2026-05-31.md
index 9368fae..81eda6c 100644
--- a/doc/reviewer/math-derivation-citation-audit-2026-05-31.md
+++ b/doc/reviewer/math-derivation-citation-audit-2026-05-31.md
@@ -16,6 +16,16 @@ Status legend: 🔴 Critical · 🟡 Important · 🔵 Polish
 > future-dated/arXiv citations) **open** → S4; **M5** (prose derivation review)
 > needs a **domain expert** (out of model scope). See
 > [`finding-orchestration.md`](finding-orchestration.md).
+>
+> **⚠️ M1 Nachkorrektur (2026-06-04):** Die ursprüngliche M1-Auflösung war selbst
+> fehlerhaft — arXiv:math/0603097 ist **Springborn 2008** (*A variational principle
+> for weighted Delaunay triangulations and hyperideal polyhedra*), nicht
+> Kolpakov–Mednykh. Kolpakov und Mednykh haben 2006 kein gemeinsames Paper
+> veröffentlicht (früheste Zusammenarbeit: 2010). Der falsche Autorenname wurde beim
+> Java→C++-Port erfunden; die Java-Quelle verlinkt korrekt auf math/0603097 ohne
+> Autorennamen. Korrekturen angewendet in: `hyper_ideal_utility.hpp`,
+> `hyper_ideal_functional.hpp`, `test_hyper_ideal_functional.cpp`,
+> `doc/math/references.md`.
 
 > **Good news up front:** `doc/math/references.md` is unusually scholarly and already
 > contains several *self-corrections* (the Glickenstein "eq. (4.6)" numbering fix →
@@ -58,8 +68,8 @@ load-bearing formula with no entry.
 
 ### Fix
 Add a `references.md` row: Kolpakov, Mednykh — *(full title)*, arXiv `math/0603097`,
-mapped to `hyper_ideal_utility.hpp`. Likewise confirm the Meyerhoff / Ushijima 2006
-volume reference (cited in code) has a row.
+mapped to `hyper_ideal_utility.hpp`. Ushijima 2006 (DOI 10.1007/0-387-29555-0_13, arXiv math/0309216) has a row —
+sole author is Ushijima; "Meyerhoff" is not a co-author (corrected 2026-06-04).
 
 ### Acceptance criteria
 - Every formula cited inline in `code/include/` has a matching `references.md` entry.
diff --git a/doc/roadmap/research-track.md b/doc/roadmap/research-track.md
index 71af0f4..99f85e2 100644
--- a/doc/roadmap/research-track.md
+++ b/doc/roadmap/research-track.md
@@ -145,10 +145,10 @@ The phase numbers match `doc/roadmap/phases.md`.
 ### Hyper-ideal volume formulas for 2- and 3-ideal-vertex faces (Phase 9b+, 🔲 planned)
 
 * **Mathematical sources:**
-  - **Kolpakov, A. & Mednykh, A.** (2012). *Spherical structures on torus
-    knots and links.* Sibirsk. Mat. Zh. 53(3), 535–541 — see the earlier
-    arXiv:math/0603097 for the one-ideal-vertex formula already implemented
-    as `calculateTetrahedronVolumeWithIdealVertexAtGamma`.
+  - **Springborn, B.** (2008). *A variational principle for weighted Delaunay
+    triangulations and hyperideal polyhedra.* J. Differential Geometry **78**(2),
+    333–367. arXiv:math/0603097 — the source of the one-ideal-vertex formula
+    already implemented as `calculateTetrahedronVolumeWithIdealVertexAtGamma`.
   - **Milnor, J.** (1982). *Hyperbolic geometry: The first 150 years.*
     Bull. Amer. Math. Soc. 6(1), 9–24.  → Volume of an ideal tetrahedron
     via Clausen function; this is the all-ideal case with 4 ideal vertices.
@@ -175,10 +175,10 @@ The phase numbers match `doc/roadmap/phases.md`.
 
 * **Acceptance criteria:**
   - Identify the correct formula for a hyper-ideal tetrahedron with exactly
-    2 ideal vertices from the literature (check Kolpakov-Mednykh generalisations
+    2 ideal vertices from the literature (check Springborn 2008 §3–4 generalisations
     and Vinberg orthoscheme decomposition).
   - Implement `calculateTetrahedronVolumeWithTwoIdealVertices(…)` analogous
-    to the existing Kolpakov-Mednykh function.
+    to the existing Springborn 2008 one-ideal-vertex function.
   - Implement `calculateTetrahedronVolumeWithThreeIdealVertices(…)` (one
     hyper-ideal + three ideal = fully cusp-like case).
   - Replace the `throw std::logic_error` in `face_energy()` with the correct
diff --git a/papers/MANUAL-DOWNLOAD.md b/papers/MANUAL-DOWNLOAD.md
new file mode 100644
index 0000000..cf43c06
--- /dev/null
+++ b/papers/MANUAL-DOWNLOAD.md
@@ -0,0 +1,63 @@
+# Manuell herunterzuladende Paper & Dissertationen
+
+Diese Paper konnten nicht automatisch geladen werden (kein freies arXiv-Preprint,
+hinter Verlag-Paywall, oder Buchkapitel).
+
+---
+
+## Dissertationen (Open Access — TU Berlin Depositonce)
+
+| Autor | Titel | Link |
+|---|---|---|
+| **Sechelmann 2016** | *Variational Methods for Discrete Surface Parameterization: Applications and Implementation* | [depositonce.tu-berlin.de/items/8e2988b2-d991-45b5-aad5-9fb7988f3b2f](https://depositonce.tu-berlin.de/items/8e2988b2-d991-45b5-aad5-9fb7988f3b2f) — CC BY-SA 4.0 |
+| **Lutz 2024** | *Decorated Discrete Conformal Equivalence, Canonical Tessellations, and Polyhedral Realization* | [doi.org/10.14279/depositonce-20357](https://doi.org/10.14279/depositonce-20357) — Open Access |
+
+---
+
+## Paper hinter Verlag-Paywall (ggf. über Institutional Access / Google Scholar)
+
+| Autor(en) | Titel | Venue | DOI / Link |
+|---|---|---|---|
+| **Ushijima** ⚠️ (Einzelautor — kein Meyerhoff!) | *A Volume Formula for Generalised Hyperbolic Tetrahedra* | Prékopa, Molnár (eds.) *Non-Euclidean Geometries*, Springer 2006 | [doi.org/10.1007/0-387-29555-0_13](https://doi.org/10.1007/0-387-29555-0_13) · arXiv [math/0309216](https://arxiv.org/abs/math/0309216) (arXiv gibt 500 für alte math/-Preprints — manuell laden) |
+| **Pinkall, Polthier** | *Computing Discrete Minimal Surfaces and Their Conjugates* | Experimental Mathematics **2**(1), 1993 | [projecteuclid.org/euclid.em/1062620735](https://projecteuclid.org/euclid.em/1062620735) |
+| **Bowers, Stephenson** | *Uniformizing dessins and Belyĭ maps via circle packing* | Memoirs AMS **170**(805), 2004 | [ams.org/books/memo/0805](https://bookstore.ams.org/memo-170-805) |
+| **Erickson, Whittlesey** | *Greedy Optimal Homotopy and Homology Generators* | SODA 2005 | [dl.acm.org/doi/10.5555/1070432.1070581](https://dl.acm.org/doi/10.5555/1070432.1070581) |
+| **Desbrun, Kanso, Tong** | *Discrete Differential Forms for Computational Modeling* | SIGGRAPH Course Notes 2006 | [dl.acm.org/doi/10.1145/1185657.1185665](https://dl.acm.org/doi/10.1145/1185657.1185665) |
+| **Soliman, Slepčev, Crane** | *Optimal Cone Singularities for Conformal Flattening* | ACM TOG **37**(4), 2018 | [doi.org/10.1145/3197517.3201367](https://doi.org/10.1145/3197517.3201367) — Autorenseite: [cs.cmu.edu/~kmcrane](https://www.cs.cmu.edu/~kmcrane/Projects/OptimalCones/index.html) |
+| **Gillespie, Springborn, Crane** | *Discrete Conformal Equivalence of Polyhedral Surfaces* | ACM TOG / SIGGRAPH 2021 | [doi.org/10.1145/3450626.3459763](https://doi.org/10.1145/3450626.3459763) — Autorenseite: [markjgillespie.com/Research/CEPS](https://markjgillespie.com/Research/CEPS/index.html) |
+| **Sharp, Soliman, Crane** | *Navigating Intrinsic Triangulations* | ACM TOG / SIGGRAPH 2019 | [doi.org/10.1145/3306346.3323042](https://doi.org/10.1145/3306346.3323042) — Autorenseite: [cs.cmu.edu/~kmcrane](https://www.cs.cmu.edu/~kmcrane/Projects/NavigatingIntrinsicTriangulations/index.html) |
+| **Alexa, Wardetzky** | *Discrete Laplacians on General Polygonal Meshes* | ACM SIGGRAPH 2011 | [doi.org/10.1145/1964921.1964997](https://doi.org/10.1145/1964921.1964997) |
+| **Bunge, Herholz, Kazhdan, Botsch** | *Polygon Laplacian Made Simple* | CGF **39**(2), 2020 | [doi.org/10.1111/cgf.13931](https://doi.org/10.1111/cgf.13931) |
+| **Rivin, Schlenker** | *The Schläfli formula in Einstein manifolds with boundary* | Electron. Res. Announc. AMS **5**, 1999 | [ams.org/era/1999-05-03](https://www.ams.org/era/1999-05-03) — wahrscheinlich frei |
+| **Bobenko, Mercat, Schmies** | *Conformal Structures and Period Matrices of Polyhedral Surfaces* | in: Bobenko, Klein (eds.) *Computational Approach to Riemann Surfaces*, LNM vol. 2013, Springer 2011, pp. 213–226 | [doi.org/10.1007/978-3-642-17413-1_7](https://doi.org/10.1007/978-3-642-17413-1_7) — Buchkapitel |
+
+---
+
+## Bücher (Bibliothek / Kauf)
+
+| Autor(en) | Titel | Verlag |
+|---|---|---|
+| **Farkas, Kra** | *Riemann Surfaces* (2. Aufl.) | Springer GTM 71 |
+| **Siegel** | *Topics in Complex Function Theory, Vol. 2* | Wiley |
+
+---
+
+## Hinweis: Autorenseiten oft freier als DOI
+
+Für die SIGGRAPH-Paper (Gillespie 2021, Sharp 2019, Soliman 2018) gibt es auf den
+CMU/Autorenseiten oft direkte PDF-Downloads ohne Paywall.
+
+---
+
+## Zitationsfehler in references.md — behoben (2026-06-07)
+
+> **arXiv:math/0603097** war in `references.md` fälschlicherweise **Kolpakov–Mednykh**
+> zugewiesen. Tatsächlich ist das der **Springborn 2008** Artikel
+> (*A variational principle for weighted Delaunay triangulations and hyperideal polyhedra*).
+> Das Autorenpaar Kolpakov & Mednykh hat 2006 kein gemeinsames Paper veröffentlicht.
+> → `references.md` wurde korrigiert (siehe PR „citation attribution fixes");
+> Springborn 2008 liegt als `springborn-2008-weighted-delaunay-hyperideal.pdf` vor.
+>
+> Ebenfalls behoben: DOI 10.1007/0-387-29555-0_13 war fälschlich „Meyerhoff, Ushijima"
+> → korrekt **Ushijima** (Einzelautor). Plus 4 weitere Korrekturen (Knöppel-DOI/arXiv,
+> Born-Bücking-Springborn Jahr, Bobenko-Mercat-Schmies Titel, fehlende vol/pages).