@article{10_2140_agt_2006_6_493,
     author = {Ekholm, Tobias},
     title = {Regular homotopy and total curvature {II:} sphere immersions into 3{\textendash}space},
     journal = {Algebraic and Geometric Topology},
     pages = {493--512},
     year = {2006},
     volume = {6},
     number = {1},
     doi = {10.2140/agt.2006.6.493},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2006.6.493/}
}