@article{1102785062, author = {Guti\'errez, M. A.}, title = {Concordance and homotopy. I. Fundamental group.}, journal = {Pacific J. Math.}, volume = {85}, number = {2}, year = {1979}, pages = { 75-91}, language = {en}, url = {http://dml.mathdoc.fr/item/1102785062} }
Gutiérrez, M. A. Concordance and homotopy. I. Fundamental group.. Pacific J. Math., Tome 85 (1979) no. 2, pp. 75-91. http://gdmltest.u-ga.fr/item/1102785062/