N. N. Bogolyubov and A. K. Prykarpatsky, “Generalized de Rham-Hodge complexes, the related characteristic Chern classes, and some applications to integrable multidimensional differential systems on Riemannian manifolds”, Ukr. Mat. Zhurn., vol. 59, no. 3, pp. 327–344, Mar. 2007.