@article{05029609, title = {Regular homotopy and total curvature I: Circle immersions into surfaces.}, journal = {Geometry \& Topology}, volume = {6}, year = {2006}, pages = {459-492}, doi = {10.2140/agt.2006.6.459}, zbl = {1113.53041}, language = {en}, url = {http://dml.mathdoc.fr/item/05029609} }
Ekholm, Tobias. Regular homotopy and total curvature I: Circle immersions into surfaces.. Geometry & Topology, Tome 6 (2006) pp. 459-492. doi : 10.2140/agt.2006.6.459. http://gdmltest.u-ga.fr/item/05029609/