@article{GDZPPN001263315,
title = {Solid varieties of semigroups.},
journal = {Semigroup forum},
volume = {48},
year = {1994},
pages = {219-234},
zbl = {0797.20045},
url = {http://dml.mathdoc.fr/item/GDZPPN001263315}
}
Denecke, K.; Wismath, S.L. Solid varieties of semigroups.. Semigroup forum, Tome 48 (1994) pp. 219-234. http://gdmltest.u-ga.fr/item/GDZPPN001263315/