@article{CMUC_1974__15_3_a1,
     author = {Bican, Ladislav and Jambor, Pavel and Kepka, Tom\'a\v{s} and N\v{e}mec, Petr},
     title = {Composition of preradicals},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {393--405},
     publisher = {mathdoc},
     volume = {15},
     number = {3},
     year = {1974},
     mrnumber = {0357468},
     zbl = {0292.16022},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1974__15_3_a1/}
}