@article{10_21136_CMJ_1991_102475,
     author = {Fabrici, Imrich},
     title = {Principal two-sided ideals in the direct product of two semigroups},
     journal = {Czechoslovak Mathematical Journal},
     pages = {411--421},
     publisher = {mathdoc},
     volume = {41},
     number = {3},
     year = {1991},
     doi = {10.21136/CMJ.1991.102475},
     mrnumber = {1117794},
     zbl = {0751.20043},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1991.102475/}
}