@article{10_21136_CMJ_1970_100959,
     author = {Zelinka, Bohdan},
     title = {Tolerance in algebraic structures},
     journal = {Czechoslovak Mathematical Journal},
     pages = {179--183},
     publisher = {mathdoc},
     volume = {20},
     number = {2},
     year = {1970},
     doi = {10.21136/CMJ.1970.100959},
     mrnumber = {0260653},
     zbl = {0197.01002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1970.100959/}
}