@article{GDZPPN00231262X, title = {On the Conjugacy Problem in a Free Product with Commuting Subgroups.}, journal = {Mathematische Annalen}, volume = {219}, year = {1976}, pages = {1-8}, zbl = {0308.20027}, url = {http://dml.mathdoc.fr/item/GDZPPN00231262X} }
Hurwitz, R. Daniel. On the Conjugacy Problem in a Free Product with Commuting Subgroups.. Mathematische Annalen, Tome 219 (1976) pp. 1-8. http://gdmltest.u-ga.fr/item/GDZPPN00231262X/