@article{MOMA_1987__104_178353,
     author = {Bruno Zimmermann},
     title = {Surfaces and the {Second} {Homology} of a {Group.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {247--254},
     publisher = {mathdoc},
     volume = {104},
     year = {1987},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1987__104_178353/}
}