@article{CM_1951__9__130_0,
author = {Loonstra, F.},
title = {The classes of partially ordered groups},
journal = {Compositio Mathematica},
volume = {9},
year = {1951},
pages = {130-140},
mrnumber = {45740},
zbl = {0043.25602},
language = {en},
url = {http://dml.mathdoc.fr/item/CM_1951__9__130_0}
}
Loonstra, F. The classes of partially ordered groups. Compositio Mathematica, Tome 9 (1951) pp. 130-140. http://gdmltest.u-ga.fr/item/CM_1951__9__130_0/