Red’kina, T. V. Some properties of the complexification of the Korteweg-de Vries equation. (Russian) Zbl 0738.35089 Izv. Akad. Nauk SSSR, Ser. Mat. 55, No. 6, 1300-1311 (1991). MSC: 35Q53 35P25 PDFBibTeX XMLCite \textit{T. V. Red'kina}, Izv. Akad. Nauk SSSR, Ser. Mat. 55, No. 6, 1300--1311 (1991; Zbl 0738.35089)
Fofana, D. An integrable system extending the Korteweg-de Vries equation. (Russian) Zbl 0743.35068 Izv. Akad. Nauk SSSR, Ser. Mat. 55, No. 6, 1287-1299 (1991). MSC: 35Q53 35P25 37J35 37K10 PDFBibTeX XMLCite \textit{D. Fofana}, Izv. Akad. Nauk SSSR, Ser. Mat. 55, No. 6, 1287--1299 (1991; Zbl 0743.35068)