@article{CMH_1976__51_139668,
     author = {F. Laudenbach},
     title = {Formes {Diff\'erentielles} de {Degr\'e} 1 {Ferm\'ees} {Non} {Singuli\`eres:} {Classes} {d'Homotopie} de leurs {Noyaux}},
     journal = {Commentarii mathematici Helvetici},
     pages = {447--464},
     publisher = {mathdoc},
     volume = {51},
     year = {1976},
     zbl = {0354.58001},
     url = {http://geodesic.mathdoc.fr/item/CMH_1976__51_139668/}
}