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3. Lu Wen (Loo Win), Yao Qiyuan, Ou Zhi (Au Chi), He Shaohui, Tao Puzhen, and He Shigiang, “A Differential Geometrical Approach for the Solution of KdV Equation,” Acta Sci. Naturalium Univ. Sunyatseni 3, 29–43 (1979) (in Chinese).
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5. Loh Ching‐Yuen, Department of Applied Mathematics, University of Western Ontario, Canada, private communication, 1982.