On a Trace Functional for Formal Pseudo-Differential Operators and the Symplectic Structure of the Korteweg-Devries Type Equation. M. Adler (1978/1979) Inventiones mathematicae
On decomposability of Nambu-Poisson tensor. Alekseevsky, D., Guha, P. (1996) Acta Mathematica Universitatis Comenianae. New Series
On the algebraic structure on the jet prolongations of fibred manifolds Ivan Kolář, Marco Modugno (1990) Czechoslovak Mathematical Journal