@string{jams = {J.~Amer. Math. Soc.}}
@article{bertram,
author = {Bertram, Aaron and Wentworth, Richard},
title = {Gromov invariants for holomorphic maps on {Riemann} surfaces},
journaltitle = jams,
date = 1996,
volume = 9,
number = 2,
pages = {529-571},
langid = {english},
langidopts = {variant=american},
shorttitle = {Gromov invariants},
annotation = {An \texttt{article} entry with a \texttt{volume} and a
\texttt{number} field},
}