@article{GDZPPN002058375,
title = {Common Singularities of Commuting Vector Fields on 2-manifolds.},
journal = {Commentarii mathematici Helvetici},
volume = {39},
year = {1964},
pages = {97-110},
zbl = {0124.16101},
url = {http://dml.mathdoc.fr/item/GDZPPN002058375}
}
Lima, Elon L. Common Singularities of Commuting Vector Fields on 2-manifolds.. Commentarii mathematici Helvetici, Tome 39 (1964) pp. 97-110. http://gdmltest.u-ga.fr/item/GDZPPN002058375/