@article{SF_1978__16_134281,
     author = {U.K. Kuspanov},
     title = {On the classes of orderable semigroups in varieties.},
     journal = {Semigroup forum},
     pages = {117--132},
     year = {1978},
     volume = {16},
     zbl = {0397.06014},
     url = {http://geodesic.mathdoc.fr/item/SF_1978__16_134281/}
}