@article{2475,
author = {Oehmke, Robert H.},
title = {A generalization of commutativity for semigroups},
journal = {Portugaliae mathematica},
volume = {24},
year = {1965},
pages = {179-187},
zbl = {0166.27805},
mrnumber = {0214680},
language = {en},
url = {http://dml.mathdoc.fr/item/2475}
}
Oehmke, Robert H. A generalization of commutativity for semigroups. Portugaliae mathematica, Tome 24 (1965) pp. 179-187. http://gdmltest.u-ga.fr/item/2475/