@article{GDZPPN001248049,
title = {The structure of orthodox unions of groups.},
journal = {Semigroup forum},
volume = {2},
year = {1971},
pages = {283-337},
zbl = {0241.20048},
url = {http://dml.mathdoc.fr/item/GDZPPN001248049}
}
Clifford, A.H. The structure of orthodox unions of groups.. Semigroup forum, Tome 2 (1971) pp. 283-337. http://gdmltest.u-ga.fr/item/GDZPPN001248049/