@article{GDZPPN00239460X,
title = {Free products of Hopf groups.},
journal = {Mathematische Zeitschrift},
volume = {85},
year = {1964},
pages = {274-284},
zbl = {0126.04803},
url = {http://dml.mathdoc.fr/item/GDZPPN00239460X}
}
Dey, I.M.S. Free products of Hopf groups.. Mathematische Zeitschrift, Tome 85 (1964) pp. 274-284. http://gdmltest.u-ga.fr/item/GDZPPN00239460X/