@article{CMUC_2008__49_1_a1,
     author = {Kravchenko, A. V.},
     title = {On the lattices of quasivarieties of differential groupoids},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {11--17},
     publisher = {mathdoc},
     volume = {49},
     number = {1},
     year = {2008},
     mrnumber = {2432816},
     zbl = {1212.08005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2008__49_1_a1/}
}