@article{GDZPPN002408937, title = {Subgroups of Knot Groups.}, journal = {Mathematische Zeitschrift}, volume = {121}, year = {1971}, pages = {99-103}, zbl = {0222.55006}, url = {http://dml.mathdoc.fr/item/GDZPPN002408937} }
Dey, I.M.S.; Cossey, J.; Meskin, S. Subgroups of Knot Groups.. Mathematische Zeitschrift, Tome 121 (1971) pp. 99-103. http://gdmltest.u-ga.fr/item/GDZPPN002408937/