@article{GDZPPN001260707,
title = {Filters and semigroup properties.},
journal = {Semigroup forum},
volume = {40},
year = {1990},
pages = {329-338},
zbl = {0702.22005},
url = {http://dml.mathdoc.fr/item/GDZPPN001260707}
}
Papazyan, T. Filters and semigroup properties.. Semigroup forum, Tome 40 (1990) pp. 329-338. http://gdmltest.u-ga.fr/item/GDZPPN001260707/