@article{2771,
author = {Rosenberg, I.G.},
title = {Special types of universal algebras preserving a relation},
journal = {Portugaliae mathematica},
volume = {34},
year = {1975},
pages = {173-188},
zbl = {0327.08008},
mrnumber = {0465992},
language = {en},
url = {http://dml.mathdoc.fr/item/2771}
}
Rosenberg, I.G. Special types of universal algebras preserving a relation. Portugaliae mathematica, Tome 34 (1975) pp. 173-188. http://gdmltest.u-ga.fr/item/2771/