@article{GDZPPN002060299, title = {Invertible Knot Cobordisms}, journal = {Commentarii mathematici Helvetici}, volume = {46}, year = {1971}, pages = {240-256}, zbl = {0227.57007}, url = {http://dml.mathdoc.fr/item/GDZPPN002060299} }
Sumners, D.W. Invertible Knot Cobordisms. Commentarii mathematici Helvetici, Tome 46 (1971) pp. 240-256. http://gdmltest.u-ga.fr/item/GDZPPN002060299/