@article{AUCMP_1989__30_1_a4,
     author = {Zejnullahu, A.},
     title = {Free left distributive semigroups},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {29--32},
     publisher = {mathdoc},
     volume = {30},
     number = {1},
     year = {1989},
     mrnumber = {1046073},
     zbl = {0705.20055},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_1989__30_1_a4/}
}