@article{GDZPPN001262785,
title = {Permutable transformation semigroups.},
journal = {Semigroup forum},
volume = {46},
year = {1993},
pages = {123-125},
zbl = {0792.20060},
url = {http://dml.mathdoc.fr/item/GDZPPN001262785}
}
Ehrenfeucht, A.; Rozenberg, G.; Harju, T. Permutable transformation semigroups.. Semigroup forum, Tome 46 (1993) pp. 123-125. http://gdmltest.u-ga.fr/item/GDZPPN001262785/