Singular evolution problems, regularization, and applications to physics, engineering, and biology Günter Lumer (1997) Banach Center Publications
Some applications of the topological degree theory to multi-valued boundary value problems [Book] Tadeusz Pruszko (1984)
Stability and Asymptotic Behavior for Certain Systems of Delay Difference Equations J. Morchało (1997) Publications de l'Institut Mathématique