Legal citation is the method lawyers use to refer to the various materials used in their writing.
The kinds of materials that lawyers use varies greatly, but they can be grouped into two basic types: primary sources and secondary sources. Primary sources are those which constitute "the law" - cases decided by the courts and legislation made by parliament.
Secondary sources are all the other materials lawyers might use - ranging from books and journal articles to newspaper reports, parliamentary debates and government reports.
Good legal citation will identify for the reader just what material is being discussed or used by the writer. It is essential for lawyers and law students to do this properly. Fortunately, it is a simple and easy-to-learn skill.