@article{CMJ_2006__56_1_a3,
     author = {Petrich, Mario},
     title = {On sandwich sets and congruences on regular semigroups},
     journal = {Czechoslovak Mathematical Journal},
     pages = {27--46},
     publisher = {mathdoc},
     volume = {56},
     number = {1},
     year = {2006},
     mrnumber = {2206285},
     zbl = {1157.20035},
     language = {en},
     url = {https://geodesic-test.mathdoc.fr/item/CMJ_2006__56_1_a3/}
}