@article{MZ_1963__81_170161, author = {Gerald Hammer}, title = {Ein {Verfahren} zur {Bestimmung} von {Begleitknoten.}}, journal = {Mathematische Zeitschrift}, pages = {395--413}, publisher = {mathdoc}, volume = {81}, year = {1963}, zbl = {0136.21202}, url = {http://geodesic.mathdoc.fr/item/MZ_1963__81_170161/} }