C -integrability test for discrete equations via multiple scale expansions. Scimiterna, Christian, Levi, Decio (2010) SIGMA. Symmetry, Integrability and Geometry: Methods and Applications [electronic only]
Conditions for integrability of a 3-form Jiří Vanžura (2017) Archivum Mathematicum We find necessary and sufficient conditions for the integrability of one type of multisymplectic 3-forms on a 6-dimensional manifold.