Παραπομπή σε μορφή APA (7η εκδ.)

Friedman, J. (2014). Sheaves on graphs, their homological invariants, and a proof of the Hanna Neumann conjecture. American Mathematical Society.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Friedman, Joel. Sheaves on Graphs, Their Homological Invariants, and a Proof of the Hanna Neumann Conjecture. Providence, R.I.: American Mathematical Society, 2014.

Παραπομπή σε μορφή MLA (9th εκδ.)

Friedman, Joel. Sheaves on Graphs, Their Homological Invariants, and a Proof of the Hanna Neumann Conjecture. American Mathematical Society, 2014.