@article{GDZPPN001263927,
title = {E-varieties of regular semigroups, relatively bifree objects and fully invariant congruences.},
journal = {Semigroup forum},
volume = {51},
year = {1995},
pages = {105-116},
zbl = {0821.20044},
url = {http://dml.mathdoc.fr/item/GDZPPN001263927}
}
Mangold, M. E-varieties of regular semigroups, relatively bifree objects and fully invariant congruences.. Semigroup forum, Tome 51 (1995) pp. 105-116. http://gdmltest.u-ga.fr/item/GDZPPN001263927/