[1] E. Dubuc, A. Kоck: On 1-form classifiers. Comm. Algebra 12(1984), 1471-1531. DOI 10.1080/00927878408823064 | MR 0744457

[2] E. Ehresmann: Extension du calcul des jets aux jets non holonomes. С R. Acad. Sci. Paris, 239(1954), 1762-1764. MR 0066734 | Zbl 0057.15603

[3] C. Ehresmann: Sur les connexions d'ordre supérieure. Atti del V° Congresso dell'Unione Mat. Italiana (1955), 344-346.

[4] A. Kоck: Formal manifolds and synthetic theory of jet bundles. Cahiers de Top. et Géom Diff. 21 (1980), 227-246. MR 0591385

[5] A. Kоck: Synthetic differential geometry. London Math. Soc. Lecture Notes Series 51, Cambridge Univ. Press, 1981. MR 0649622

[6] A. Kоck: Differential forms with values in groups. Bull. Austral. Math. Soc. 25 (1982), 357-386. DOI 10.1017/S0004972700005426 | MR 0671484

[7] A. Kоck: A combinatorial theory of connections. in Mathematical Applications of Category Theory, Proceedings, Denver, 1983.

[8] I. Kolář: Some higher order operations with connections. Czechoslovak Math. J. 24 (1974), 311-330. MR 0356114

[9] J. Virsik: On the holonomity of higher order connections. Cahiers de Top et Géom Diff. 12 (1971), 197-212. MR 0305294 | Zbl 0223.53026