@article{ARM_1985_21_1_a1,
     author = {Chajda, Ivan},
     title = {Varieties with tolerance and congruence extension property},
     journal = {Archivum mathematicum},
     pages = {5--12},
     year = {1985},
     volume = {21},
     number = {1},
     mrnumber = {818302},
     zbl = {0575.08001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1985_21_1_a1/}
}