Contracts materials are generally found in the call number range KF801-KF839.
Related Subject Headings include:
Breach of contract -- United States
Unjust enrichment -- United States
Contracts : examples & explanations by 
Contracts: Essay & multiple choice exams (Friedman's Practice Series) by 
Acing contracts : a checklist approach to contracts law by 
Chirelstein's Concepts and Case Analysis in the Law of Contracts, 7th (Concepts and Insights Series) by 
Principles of contract law by 
Calamari and Perillo on contracts by 
Contracts in a nutshell by E. Allen Farnsworth, Contracts (4th ed. 2004) 9th floor - KF801 .F36
Howard O. Hunter, Modern Law of Contracts (2d rev. ed. 1999-date) 9th floor - KF801 .H85, available in Westlaw
John Edward Murray, Jr., Murray on Contracts (4th ed. 2001) 9th floor - KF801 .M964, available in Lexis
Joseph M. Perillo, Calamari and Perillo on Contracts (5th ed. 2003) 6th floor - Reserve & Academic Success KF801 .C125
E. Allan Farnsworth, Farnsworth on Contracts (3d ed. 2004-date) 9th floor - KF801 .F37
Richard A. Lord, Williston: A Treatise on the law of Contracts (4th ed. 1990-date) 9th floor KF801.W68 J176x , available in Westlaw
Corbin on Contracts (Joseph M. Perillo ed., rev. ed.1993-date) 6th floor - Reserve KF801 .C811x, available in Lexis