BibTeX: 
@article{Relational_PathsAFP,
author = {Walter Guttmann and Peter Höfner},
title = {Relational Characterisations of Paths},
journal = {Archive of Formal Proofs},
month = jul,
year = 2020,
note = {\url{http://isaafp.org/entries/Relational_Paths.html},
Formal proof development},
ISSN = {2150914x},
}
