The Grackle library was born out of the chemistry and cooling routines of the Enzo simulation code. As such, all of those who have contributed to Enzo development, and especially to the chemistry and cooling, have contributed to the Grackle.
If you used the Grackle library in your work, please cite it as "the Grackle chemistry and cooling library (Smith et al. 2017)"
Smith, B.D., Bryan, G.L., Glover, S.C.O., et al. 2017, MNRAS, 466, 2217
Additionally, please add a footnote to: https://grackle.readthedocs.io/
For LaTex and BibTex users, here is a copy of the bibitem entry
\bibitem[Smith et al.(2017)]{2017MNRAS.466.2217S} Smith, B.~D., Bryan, G.~L., Glover, S.~C.~O., et al.\ 2017, \mnras, 466, 2217and here is a copy of the Bibtext entry:
@ARTICLE{2017MNRAS.466.2217S,
author = {{Smith}, B.~D. and {Bryan}, G.~L. and {Glover}, S.~C.~O. and
{Goldbaum}, N.~J. and {Turk}, M.~J. and {Regan}, J. and {Wise}, J.~H. and
{Schive}, H.-Y. and {Abel}, T. and {Emerick}, A. and {O'Shea}, B.~W. and
{Anninos}, P. and {Hummels}, C.~B. and {Khochfar}, S.},
title = "{GRACKLE: a chemistry and cooling library for astrophysics}",
journal = {\mnras},
archivePrefix = "arXiv",
eprint = {1610.09591},
keywords = {astrochemistry, methods: numerical, galaxies: formation},
year = 2017,
month = apr,
volume = 466,
pages = {2217-2234},
doi = {10.1093/mnras/stw3291},
adsurl = {http://adsabs.harvard.edu/abs/2017MNRAS.466.2217S},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}