@article{01883664, title = {Vector fields on nonorientable surfaces.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {2003}, year = {2003}, pages = {133-152}, doi = {10.1155/S0161171203204038}, zbl = {1011.30034}, language = {en}, url = {http://dml.mathdoc.fr/item/01883664} }
Barza, Ilie; Ghisa, Dorin. Vector fields on nonorientable surfaces.. International Journal of Mathematics and Mathematical Sciences, Tome 2003 (2003) pp. 133-152. doi : 10.1155/S0161171203204038. http://gdmltest.u-ga.fr/item/01883664/