1. Bell 2015: ‘The Axiom of Choice’. John L. Bell, in: the Stanford Encyclopedia of Philosophy, erst veröffentlicht 2008. Online at https://plato.stanford.edu/entries/axiom-choice/.
2. Budiansky 2021: Journey to the Edge of Reason: The Life of Kurt Gödel. Stephen Budiansky, W.W. Norton/Oxford Univ. Press/Ullstein (2021). ISBN: 978-1-324-00544-5.
3. Buss 1994: ‘On Gödel’s Theorems on Lengths of Proofs I: Number of Lines and Speedups for Arithmetic’. Samuel Buss, in: the Journal of Symbolic Logic, Band 39 (1994), S. 737–756.
4. Buss 1995: ‘On Gödel’s Theorems on Lengths of Proofs II: Lower Bounds for Recognizing k Symbol Provability’. Samuel Buss, in: Feasible Mathematics II, Birkhauser (1995), S. 57–90.
5. Cook 2010: ‘Zermelo-Fraenkel Set Theory with the Axiom of Choice’. William J. Cook, math. Infoblatt (2010). Im Internet : https://billcookmath.com/courses/math2510-spring2010/ZFC.pdf.