@article{SF_1986__33_134810,
     author = {D.J. Hansen},
     title = {Bistable orderings on a certain class of semigroups.},
     journal = {Semigroup forum},
     pages = {265--268},
     publisher = {mathdoc},
     volume = {33},
     year = {1986},
     zbl = {0586.06006},
     url = {http://geodesic.mathdoc.fr/item/SF_1986__33_134810/}
}