@article{10_4153_CJM_1995_030_5,
     author = {Langevin, R\'emi and Levitt, Gilbert and Rosenberg, Harold},
     title = {Classes {D'homotopie} de {Surfaces} {Avec} {Rebroussements} et {Queues} {D'aronde} dans {R3}},
     journal = {Canadian journal of mathematics},
     pages = {544--572},
     year = {1995},
     volume = {47},
     number = {3},
     doi = {10.4153/CJM-1995-030-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1995-030-5/}
}