@article{PORMA_1965__24_4_114965,
     author = {Oehmke, Robert H.},
     title = {A generalization of commutativity for semigroups},
     journal = {Portugaliae mathematica},
     pages = {179--187},
     publisher = {mathdoc},
     volume = {24},
     number = {4},
     year = {1965},
     mrnumber = {0214680},
     zbl = {0166.27805},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1965__24_4_114965/}
}