The following legislation might be useful to your research. To find other tax-related law, search CanLII.
Statutes are passed by the federal government and in each provincial jurisdiction each year. Statutes passed may be new statutes or amendments of earlier statutes. The law, then, is the original act and any subsequent amendments to that act. Periodically, statutes and their amendments are gathered together and reissued as "Revised Statutes." Statutes are designated as statutes (S) or revised statutes (R.S.). There is also supporting legislation called "Regulations."
You can locate Canadian statutes online using CanLII or official government websites (e.g., Government of Canada, Nova Scotia), and print versions are available in the Primary Sources Room on the second floor of the library. Statutes for US, UK, and Commonwealth countries are also available in the Primary Sources Room.