@incollection{Tretkoff:1984:CGT,
author = {Tretkoff, C. L. and Tretkoff, M. D.},
title = {Combinatorial Group Theory, {R}iemann Surfaces and
Differential Equations},
booktitle = {Contributions to Group Theory},
series = {Contemp. Math.},
volume = {33},
pages = {467–519},
publisher = {Amer. Math. Soc.},
address = {Providence, RI},
year = {1984},
mrclass = {30F10 (12H05 20D60 20G20 22E40 34A99)},
mrnumber = {MR0767125 (86g:30055)},
mrreviewer = {William Harvey},
zblno = {0557.30036}}