@article{10_21136_CMJ_1985_102021,
     author = {Pond\v{e}l{\'\i}\v{c}ek, Bed\v{r}ich},
     title = {Modularity and distributivity of tolerance lattices of commutative separative semigroups},
     journal = {Czechoslovak Mathematical Journal},
     pages = {333--337},
     publisher = {mathdoc},
     volume = {35},
     number = {2},
     year = {1985},
     doi = {10.21136/CMJ.1985.102021},
     mrnumber = {787135},
     zbl = {0573.20062},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1985.102021/}
}