@article{GDZPPN002061597, title = {Commutators of Diffeomorphisms: II.}, journal = {Commentarii mathematici Helvetici}, volume = {50}, year = {1975}, pages = {33-40}, zbl = {0299.58008}, url = {http://dml.mathdoc.fr/item/GDZPPN002061597} }
Mather, John N. Commutators of Diffeomorphisms: II.. Commentarii mathematici Helvetici, Tome 50 (1975) pp. 33-40. http://gdmltest.u-ga.fr/item/GDZPPN002061597/