@article{10_21136_CMJ_1994_128457,
     author = {Jakub{\'\i}k, J\'an},
     title = {On convexities of $d$-groups},
     journal = {Czechoslovak Mathematical Journal},
     pages = {305--314},
     publisher = {mathdoc},
     volume = {44},
     number = {2},
     year = {1994},
     doi = {10.21136/CMJ.1994.128457},
     mrnumber = {1281025},
     zbl = {0821.06014},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1994.128457/}
}