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@article{PORMA_1994__51_2_47203, author = {Ben Yakoub, L.}, title = {On a theorem of {P.} {E.} {Schupp.} {(Sur} un th\'eor\`eme de {P.} {E.} {Schupp.)}}, journal = {Portugaliae mathematica}, pages = {231--233}, publisher = {mathdoc}, volume = {51}, number = {2}, year = {1994}, zbl = {0818.16028}, language = {en}, url = {http://geodesic.mathdoc.fr/item/PORMA_1994__51_2_47203/} }
Ben Yakoub, L. On a theorem of P. E. Schupp. (Sur un théorème de P. E. Schupp.). Portugaliae mathematica, Tome 51 (1994) no. 2, pp. 231-233. http://geodesic.mathdoc.fr/item/PORMA_1994__51_2_47203/