@article{1256054445, author = {Haken, Wolfgang}, title = {Trivial loops in homotopy $3$-spheres}, journal = {Illinois J. Math.}, volume = {11}, number = {4}, year = {1967}, pages = { 547-554}, language = {en}, url = {http://dml.mathdoc.fr/item/1256054445} }
Haken, Wolfgang. Trivial loops in homotopy $3$-spheres. Illinois J. Math., Tome 11 (1967) no. 4, pp. 547-554. http://gdmltest.u-ga.fr/item/1256054445/