@article{CMUC_1974__15_1_a6,
     author = {Bican, Ladislav and Jambor, Pavel and Kepka, Tom\'a\v{s} and N\v{e}mec, Petr},
     title = {Preradicals},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {75--83},
     publisher = {mathdoc},
     volume = {15},
     number = {1},
     year = {1974},
     mrnumber = {0347906},
     zbl = {0277.16020},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1974__15_1_a6/}
}