@article{SF_1978__16_134284,
     author = {F.R. McMorris and C.S. Johnson},
     title = {Abian's order relation for semigroups.},
     journal = {Semigroup forum},
     pages = {147--152},
     publisher = {mathdoc},
     volume = {16},
     year = {1978},
     zbl = {0385.06021},
     url = {http://geodesic.mathdoc.fr/item/SF_1978__16_134284/}
}