@article{SF_1989__38_2_134946,
     author = {Thomas E. Nordahl},
     title = {Separative {P.I.} semigroups are embeddable into a semilattice of groups.},
     journal = {Semigroup forum},
     pages = {119--122},
     publisher = {mathdoc},
     volume = {38},
     number = {2},
     year = {1989},
     zbl = {0657.20048},
     url = {http://geodesic.mathdoc.fr/item/SF_1989__38_2_134946/}
}