@article{GDZPPN001261878,
title = {Extension properties of WS-groups.},
journal = {Semigroup forum},
volume = {44},
year = {1992},
pages = {63-70},
zbl = {0774.43005},
url = {http://dml.mathdoc.fr/item/GDZPPN001261878}
}
Troallic, J.P.; Hansel, G. Extension properties of WS-groups.. Semigroup forum, Tome 44 (1992) pp. 63-70. http://gdmltest.u-ga.fr/item/GDZPPN001261878/