@article{MOMA_1994__118_3-4_178653,
     author = {H.A. Biagioni},
     title = {Generalized {Solutions} to {Nonlinear} {First-Order} {Systems.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {7--20},
     publisher = {mathdoc},
     volume = {118},
     number = {3-4},
     year = {1994},
     zbl = {0807.35020},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1994__118_3-4_178653/}
}