- Henry Chan: Measure Zero.
- Henry Chan: Notes on Hyperbolic Geometry.
- Elden Elmanto: Lecture Notes.

- Part 1: Scissors congruence in the line.
- Part 2: Group theory exercises.
- Part 3: More on group theory.
- Part 4: Group homology.

- Rich Schwartz, The Dehn-Sydler Theorem Explained.
- Borge Jessen, The algebra of polydera and the Dehn-Sydler theorem.
- Borge Jessen, Jorgen Karpf, Anders Thorup, Some functional equations in groups and rings.