Sometimes you need to find what a particular abbreviation stands for in order to track down the reporter or journal, and other times, you might need to find the abbreviation for a journal or reporter in order to cite it. There are a number of places to check.
Canadian Guide to Uniform Legal Citation, 10th edition by 
Canadian Abridgment's Table of Abbreviations
Index to Legal Citations and Abbreviations by 
Prince's Bieber Dictionary of Legal Abbreviations by 