There is a growing body of literature in this area.
Here are some volumes that might help you get started:
Feldman, Weil and Biederman. Art Law. I & II Little, Brown, 1986
Malaro. A Legal Primer on Managing Museum Collections. Smithsonian,
1985
Merryman and Elsen. Law, Ethics and the Visual Arts. I & II Penn,
1987
Phelan. Museums and the Law. AASLH, 1982