Goldschmidt, H. Integrability criteria for systems of nonlinear partial differential equations. (English) Zbl 0159.14101 J. Differ. Geom. 1, 269-307 (1967). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 1 ReviewCited in 81 Documents MathOverflow Questions: Principal symbol for non-linear differential operators Keywords:partial differential equations PDF BibTeX XML Cite \textit{H. Goldschmidt}, J. Differ. Geom. 1, 269--307 (1967; Zbl 0159.14101) Full Text: DOI OpenURL