@article{CMUC_2008__49_4_a1,
     author = {Chajda, Ivan},
     title = {Pseudocomplemented directoids},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {533--539},
     publisher = {mathdoc},
     volume = {49},
     number = {4},
     year = {2008},
     mrnumber = {2493936},
     zbl = {1212.06005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2008__49_4_a1/}
}