@article{GDZPPN001253182,
title = {A theorem on binary relations and infinite languages.},
journal = {Semigroup forum},
volume = {18},
year = {1979},
pages = {307-316},
zbl = {0425.20053},
url = {http://dml.mathdoc.fr/item/GDZPPN001253182}
}
Schwarz, Stefan. A theorem on binary relations and infinite languages.. Semigroup forum, Tome 18 (1979) pp. 307-316. http://gdmltest.u-ga.fr/item/GDZPPN001253182/