@article{GDZPPN002319128, title = {An Abelian Quotient of the Mapping Class Group ...g.}, journal = {Mathematische Annalen}, volume = {250}, year = {1980}, pages = {225-242}, zbl = {0409.57009}, url = {http://dml.mathdoc.fr/item/GDZPPN002319128} }
Johnson, Dennis. An Abelian Quotient of the Mapping Class Group ...g.. Mathematische Annalen, Tome 250 (1980) pp. 225-242. http://gdmltest.u-ga.fr/item/GDZPPN002319128/