W. Babiański, R. Bittner and L. Latecki, The criteria for the existence of derivatives, primitives and limit condition in groups, in: Conference on Complex Analysis and Applications, Varna 1987, Bulg. Acad. Sci., 1987, 11-22.
 W. Babiański, R. Bittner and L. Latecki, The criteria for the existence and uniqueness of solutions of abstract differential equations, Fasc. Math. 19 (1990), 15-19.
 W. Babiański and R. Bittner, Nonlinear operational calculus, in: Generalised Functions and Convergence, World Scientific, Singapore, 1988, 73-87.