@article{SF_1984__28_134653,
     author = {S. Premchand},
     title = {ndependence of axioms for biordered sets.},
     journal = {Semigroup forum},
     pages = {249--264},
     publisher = {mathdoc},
     volume = {28},
     year = {1984},
     zbl = {0533.20028},
     url = {http://geodesic.mathdoc.fr/item/SF_1984__28_134653/}
}