@article{GDZPPN00125023X,
title = {On the elementary theory of free inverse semigroups.},
journal = {Semigroup forum},
volume = {7},
year = {1974},
pages = {189-195},
zbl = {0299.20050},
url = {http://dml.mathdoc.fr/item/GDZPPN00125023X}
}
Vazenin, Ju.M. On the elementary theory of free inverse semigroups.. Semigroup forum, Tome 7 (1974) pp. 189-195. http://gdmltest.u-ga.fr/item/GDZPPN00125023X/