@article{MAN_1971__193_182725,
     author = {Paul E. SCHUPP},
     title = {Small {Cancellation} {Theory} over {Free} {Products} with {Amalgamation.}},
     journal = {Mathematische Annalen},
     pages = {255--264},
     publisher = {mathdoc},
     volume = {193},
     year = {1971},
     zbl = {0209.05204},
     url = {http://geodesic.mathdoc.fr/item/MAN_1971__193_182725/}
}