BibTeX: 
@article{LocallyNamelessSigmaAFP,
author = {Ludovic Henrio and Florian KammÃ¼ller and Bianca Lutz and Henry Sudhof},
title = {Locally Nameless Sigma Calculus},
journal = {Archive of Formal Proofs},
month = apr,
year = 2010,
note = {\url{https://isaafp.org/entries/LocallyNamelessSigma.html},
Formal proof development},
ISSN = {2150914x},
}
