@article{RSMUP_1983__69__37_0,
     author = {Cattabriga, Lamberto},
     title = {A remark on certain overdetermined systems of partial differential equations},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {37--40},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {69},
     year = {1983},
     mrnumber = {716983},
     zbl = {0551.35062},
     language = {en},
     url = {http://archive.numdam.org/item/RSMUP_1983__69__37_0/}
}