@article{ARM_1986__22_3_a4,
     author = {Dr\'a\v{s}il, Milan},
     title = {On languages linearly grammatizable by means of derivatives},
     journal = {Archivum mathematicum},
     pages = {139--144},
     publisher = {mathdoc},
     volume = {22},
     number = {3},
     year = {1986},
     mrnumber = {868129},
     zbl = {0627.68061},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1986__22_3_a4/}
}