@article{AUPO_1973__13_1_a3,
     author = {Rach\r{u}nek, Ji\v{r}{\'\i}},
     title = {Directed convex subgroups of ordered groups},
     journal = {Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica},
     pages = {39--46},
     publisher = {mathdoc},
     volume = {13},
     number = {1},
     year = {1973},
     mrnumber = {0357273},
     zbl = {0292.06005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUPO_1973__13_1_a3/}
}