D11-4-19, The Determination of When Goods are Entitled to the Benefit of the United States Tariff, Mexico Tariff or Mexico-United States Tariff under NAFTA
https://www.cbsa-asfc.gc.ca/publications/dm-md/d11/d11-4-19-eng.html
D11-4-19 has undergone a change to its title. The Mexico-United States Tariff (MUST) used under the North American Free Trade Agreement (NAFTA) cannot be used for the Canada-United States-Mexico Agreement (CUSMA). The MUST will remain in place in the interim, for adjustments pertaining to importations that occurred while the NAFTA was in effect.
D11-4-35, The Determination of When Goods are Entitled to the Benefit of the United States Tariff or Mexico Tariff under CUSMA
https://www.cbsa-asfc.gc.ca/publications/dm-md/d11/d11-4-35-eng.html
D11-4-35 addresses the determination of when goods are entitled to benefit from the United States Tariff or the Mexico Tariff under the Canada-United States-Mexico Agreement (CUSMA).