@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/