@article{GDZPPN001254189,
title = {Subsemigroups of the finite complexes of a group.},
journal = {Semigroup forum},
volume = {20},
year = {1980},
pages = {285-292},
zbl = {0456.20035},
url = {http://dml.mathdoc.fr/item/GDZPPN001254189}
}
Pedersen, F.P.; Sizer, W.S. Subsemigroups of the finite complexes of a group.. Semigroup forum, Tome 20 (1980) pp. 285-292. http://gdmltest.u-ga.fr/item/GDZPPN001254189/