Ehresmann, Charles; Libermann, Paulette Sur les formes différentielles exterieures de degré 2. (French) Zbl 0034.19903 C. R. Acad. Sci., Paris 227, 420-421 (1948). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 3 Documents Keywords:Partial differential equations PDFBibTeX XMLCite \textit{C. Ehresmann} and \textit{P. Libermann}, C. R. Acad. Sci., Paris 227, 420--421 (1948; Zbl 0034.19903)