Cannot parse BibTeX from Papers.app

[JonnyBurger]

The app Papers for Mac produces the following BibTeX:

@article{vanWoesik:2006ti,
author = {van Woesik, R and Lacharmoise, F and Koksal, S},
title = {{Annual cycles of solar insulation predict spawning times of Caribbean corals}},
journal = {Ecology Letters},
year = {2006},
volume = {9},
pages = {390--398},
month = jan
}

The problematic part is month = jan, it's not month = {jan}.
bibtexParseJs has trouble parsing this BibTeX.

/cc @lucaspelloni2

[retorquere]

month = jan is valid bibtex though. It behaves as if there was a @string{jan = {1}}.