@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/