@article{10_21136_CMJ_1990_102396,
     author = {Pond\v{e}l{\'\i}\v{c}ek, Bed\v{r}ich},
     title = {Tolerance modular varieties of semigroups},
     journal = {Czechoslovak Mathematical Journal},
     pages = {441--452},
     publisher = {mathdoc},
     volume = {40},
     number = {3},
     year = {1990},
     doi = {10.21136/CMJ.1990.102396},
     mrnumber = {1065023},
     zbl = {0731.20039},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1990.102396/}
}