@article{MV_1973_25_1_a28,
     author = {D. N. Krgovi\'c},
     title = {Notes on regular semigroups},
     journal = {Matemati\v{c}ki vesnik},
     pages = {237 },
     publisher = {mathdoc},
     volume = {25},
     number = {1},
     year = {1973},
     url = {http://geodesic.mathdoc.fr/item/MV_1973_25_1_a28/}
}