@article{MS2_1967__20_165999,
     author = {Victor Klee and Czeslaw Olech},
     title = {Characterizations of a {Class} of {Convex} {Sets.}},
     journal = {Mathematica Scandinavica},
     pages = {290--296},
     publisher = {mathdoc},
     volume = {20},
     year = {1967},
     zbl = {0162.44104},
     url = {http://geodesic.mathdoc.fr/item/MS2_1967__20_165999/}
}