Geometric aspects of high-order eigenvalue problems I. Structures on spaces of boundary conditions. - Xifang Cao; Hongyou Wu (Int. J. Math. Math. Sci., 2004)

On classification of Bäcklund transformations. - Xifang Cao; Ying Chen (Appl. Math. Comput., 2011)

Bäcklund transformations with two pseudo-potentials. - Xifang Cao (Appl. Math. Lett., 2016)