@article{10_21136_CMJ_1987_102138,
     author = {Sait\^o, T\^oru},
     title = {Archimedean classes in an ordered semigroup. {IV}},
     journal = {Czechoslovak Mathematical Journal},
     pages = {86--119},
     publisher = {mathdoc},
     volume = {37},
     number = {1},
     year = {1987},
     doi = {10.21136/CMJ.1987.102138},
     mrnumber = {875131},
     zbl = {0669.20048},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1987.102138/}
}