[1] BISHOP R. L., GRITTENDEN R. J.: Geometrie of manifolds. MIR Moskva 1967.
[2] EHRESMANN C:
Extension du calcul des jet aux jets non-holonomes. CRAS Paris, 239, 1954, 1762-1964.
MR 0066734
[3] GODBILLON C: Géometrie différentielle et méchanique analytique. MIR Moskva 1973.
[4] GOLDSCHMIDT G.:
Integrability criteria for systems of non-linear partial diff. equations. J. Diff. Geom., 1, 1967, 269-307.
MR 0226156