@article{460441, recid = {460441}, author = {Fenchel, W. and Nielsen, Jakob, and Schmidt, Asmus L.}, title = {Discontinuous groups of isometries in the hyperbolic plane [electronic resource] /}, publisher = {Walter de Gruyter,}, address = {Berlin ;}, pages = {xxi, 364 p. :}, year = {2003}, url = {http://library.usi.edu/record/460441}, }