Superposition formulae for nonlinear integrable equations in bilinear form

We are concerned with superposition formulae and Bianchi identities related to bilinear Bäcklund transformations for nonlinear integrable equations in bilinear form. Illustrating examples show that bilinear Bäcklund transformations and their associated superposition formulae may be utilized to generate soliton solutions, rational solutions and some other special solutions to nonlinear integrable equations under consideration.