@article{GDZPPN002063980, title = {Om multiple points of smooth immersions.}, journal = {Commentarii mathematici Helvetici}, volume = {55}, year = {1980}, pages = {521-527}, zbl = {0457.57013}, url = {http://dml.mathdoc.fr/item/GDZPPN002063980} }
Ronga, Felice. Om multiple points of smooth immersions.. Commentarii mathematici Helvetici, Tome 55 (1980) pp. 521-527. http://gdmltest.u-ga.fr/item/GDZPPN002063980/