@article{10_21136_CMJ_1988_102214,
     author = {Chajda, Ivan and Zelinka, Bohdan},
     title = {Tolerances and congruences on implication algebras},
     journal = {Czechoslovak Mathematical Journal},
     pages = {207--217},
     publisher = {mathdoc},
     volume = {38},
     number = {2},
     year = {1988},
     doi = {10.21136/CMJ.1988.102214},
     mrnumber = {946288},
     zbl = {0678.08003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1988.102214/}
}