@article{GDZPPN002063972, title = {Poincar\'e duality groups of dimension two.}, journal = {Commentarii mathematici Helvetici}, volume = {55}, year = {1980}, pages = {510-520}, zbl = {0458.20048}, url = {http://dml.mathdoc.fr/item/GDZPPN002063972} }
Eckmann, Beno; Müller, Heinz. Poincaré duality groups of dimension two.. Commentarii mathematici Helvetici, Tome 55 (1980) pp. 510-520. http://gdmltest.u-ga.fr/item/GDZPPN002063972/