@article{MAN_1968__178_161738,
     author = {P.E. SCHUPP},
     title = {On {Dehn's} {Algorithm} and the {Conjugacy} {Problem.}},
     journal = {Mathematische Annalen},
     pages = {119--130},
     publisher = {mathdoc},
     volume = {178},
     year = {1968},
     zbl = {0164.01901},
     url = {http://geodesic.mathdoc.fr/item/MAN_1968__178_161738/}
}