@article{GDZPPN001264893, title = {Z-mappings and a classification theorem.}, journal = {Semigroup forum}, volume = {53}, year = {1996}, pages = {349-356}, zbl = {0847.06001}, url = {http://dml.mathdoc.fr/item/GDZPPN001264893} }
Shi, G.B.; Wang, G.P. Z-mappings and a classification theorem.. Semigroup forum, Tome 53 (1996) pp. 349-356. http://gdmltest.u-ga.fr/item/GDZPPN001264893/