@article{10_21136_CMJ_1988_102216,
     author = {Pond\v{e}l{\'\i}\v{c}ek, Bed\v{r}ich},
     title = {Commutative semigroups whose lattice of tolerances is {Boolean}},
     journal = {Czechoslovak Mathematical Journal},
     pages = {226--230},
     publisher = {mathdoc},
     volume = {38},
     number = {2},
     year = {1988},
     doi = {10.21136/CMJ.1988.102216},
     mrnumber = {946290},
     zbl = {0657.20052},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1988.102216/}
}