@article{CMUC_1971__12_2_a8,
     author = {Bure\v{s}, Jarol{\'\i}m},
     title = {Differential operators and $G$-structures of higher order},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {327--335},
     publisher = {mathdoc},
     volume = {12},
     number = {2},
     year = {1971},
     mrnumber = {0293530},
     zbl = {0216.43703},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1971__12_2_a8/}
}