@article{GDZPPN001261355,
title = {Normal semigroups of partial one-to-one transformations II.},
journal = {Semigroup forum},
volume = {43},
year = {1991},
pages = {344-356},
zbl = {0734.20031},
url = {http://dml.mathdoc.fr/item/GDZPPN001261355}
}
Williams, W.; Levi, I. Normal semigroups of partial one-to-one transformations II.. Semigroup forum, Tome 43 (1991) pp. 344-356. http://gdmltest.u-ga.fr/item/GDZPPN001261355/