@article{CMUC_1968__9_1_a12,
     author = {Zelinka, Bohdan},
     title = {Tolerance graphs},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {121--131},
     publisher = {mathdoc},
     volume = {09},
     number = {1},
     year = {1968},
     mrnumber = {0232698},
     zbl = {0155.51206},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1968__9_1_a12/}
}