@article{1183555720, author = {Johannson, Klaus}, title = {Heegaard surfaces in Haken 3-manifolds}, journal = {Bull. Amer. Math. Soc. (N.S.)}, volume = {23}, number = {1}, year = {1990}, pages = { 91-98}, language = {en}, url = {http://dml.mathdoc.fr/item/1183555720} }
Johannson, Klaus. Heegaard surfaces in Haken 3-manifolds. Bull. Amer. Math. Soc. (N.S.), Tome 23 (1990) no. 1, pp. 91-98. http://gdmltest.u-ga.fr/item/1183555720/