@article{01295605,
title = {Generalized Hecke groups and Hecke polygons.},
journal = {Annales Academiae Scientiarum Fennicae. Mathematica},
volume = {24},
year = {1999},
pages = {187-214},
zbl = {0926.30026},
language = {en},
url = {http://dml.mathdoc.fr/item/01295605}
}
Huang, Shuechin. Generalized Hecke groups and Hecke polygons.. Annales Academiae Scientiarum Fennicae. Mathematica, Tome 24 (1999) pp. 187-214. http://gdmltest.u-ga.fr/item/01295605/