BibTeX: 
@article{RecursionAdditionAFP,
author = {Georgy Dunaev},
title = {Recursion Theorem in ZF},
journal = {Archive of Formal Proofs},
month = may,
year = 2020,
note = {\url{http://isaafp.org/entries/RecursionAddition.html},
Formal proof development},
ISSN = {2150914x},
}
