Residential segregation took various forms. Some state constitutions (such as that of that of California) had clauses giving local jurisdictions the right to regulate where members of certain "races" could live. Restrictive covenants in deeds had prevented minorities from purchasing properties from any subsequent owner. In the 1948 case of "Shelley v. Kraemer", the US Supreme Court ruled that such covenants were unenforceable in a court of law. Residential segregation patterns had already become established in most American cities, but they have taken new forms in areas of increased immigration. New immigrant populations have typically moved into older areas to become established, and that pattern of population succession is seen in many areas. Many ethnic populations appear to prefer to live in areas of concentration, with their own foods, stores, religious institutions and other familiar services. People from a village or region often resettle close together in new areas, even as they move into suburban areas.