Regulations are a part of the law that communicate the intent of legislation. The Value for Duty Regulations, Direct Shipment of Goods Regulations and the Purchaser in Canada Regulations each provide information on the valuation provisions of the Customs Act.
D13-1-1
Valuation for Duty Regulations
D13-1-2
Direct Shipment of Goods Regulations
D13-1-3
Customs Valuation: Purchaser in Canada Regulation (Customs Act, Section 48)