@article{CMUC_1975__16_2_a8,
     author = {Zelinka, Bohdan},
     title = {Tolerance relations on semilattices},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {333--338},
     publisher = {mathdoc},
     volume = {16},
     number = {2},
     year = {1975},
     mrnumber = {0369199},
     zbl = {0326.06004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1975__16_2_a8/}
}