@article{SF_1977__15_134260,
     author = {J. M. Firsov},
     title = {Semimodules over ordered rings.},
     journal = {Semigroup forum},
     pages = {283--294},
     publisher = {mathdoc},
     volume = {15},
     year = {1977},
     zbl = {0379.20052},
     url = {http://geodesic.mathdoc.fr/item/SF_1977__15_134260/}
}