@article{MZ_1974__138_172102,
     author = {Kennth I. Appel},
     title = {On the {Conjugacy} {Problem} for {Knot} {Groups.}},
     journal = {Mathematische Zeitschrift},
     pages = {273--294},
     publisher = {mathdoc},
     volume = {138},
     year = {1974},
     zbl = {0276.20033},
     url = {http://geodesic.mathdoc.fr/item/MZ_1974__138_172102/}
}