Cabibbo-Kobayashi-Maskawa Mixing in Superstring derived Standard-like Models

We examine the problem of three generation quark flavour mixing in realistic, superstring derived standard-like models, constructed in the free fermionic formulation. We study the sources of family mixing in these models and discuss the necessary conditions to obtain a realistic Cabibbo-Kobayashi-Maskawa (CKM) Mixing matrix. In a specific model, we estimate the mixing angles and discuss the weak CP violating phase. We agree that the superstring standard-like models can produce a realistic CKM mixing matrix. We discuss the possible textures of quark mass matrices that may be obtained in these models. (authors)