Be sure to clarify with your professor what citation style you should use to cite legal sources (e.g. Bluebook: A Uniform System of Citation (Ready REF KF245 .B4), and The Complete Guide to Citing Government Documents (REF J83 .G37).
This online guide prepared by Peter W. Martin at Cornell University School of Law, is an abridgement of the more detailed Bluebook: a uniform system of citation (Ready Ref KF 245 .B4).