@article{SF_1974__7_134010,
     author = {T\^oru Sait\^o},
     title = {The orderability of idempotent semigroups.},
     journal = {Semigroup forum},
     pages = {264--285},
     publisher = {mathdoc},
     volume = {7},
     year = {1974},
     zbl = {0276.06010},
     url = {http://geodesic.mathdoc.fr/item/SF_1974__7_134010/}
}