@article{GDZPPN001255479, title = {P-systems in regular semigroups.}, journal = {Semigroup forum}, volume = {24}, year = {1982}, pages = {173-188}, zbl = {0479.20030}, url = {http://dml.mathdoc.fr/item/GDZPPN001255479} }
Yamada, M. P-systems in regular semigroups.. Semigroup forum, Tome 24 (1982) pp. 173-188. http://gdmltest.u-ga.fr/item/GDZPPN001255479/