@article{ARM_1976__12_4_a6,
     author = {Fuchs, Jarom{\'\i}r},
     title = {On closure operators on monoids},
     journal = {Archivum mathematicum},
     pages = {225--232},
     publisher = {mathdoc},
     volume = {12},
     number = {4},
     year = {1976},
     mrnumber = {0435268},
     zbl = {0363.20059},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1976__12_4_a6/}
}