Treaties and other international acts series. 5301. Boundary waters, pilotage services on Great Lakes and St. Lawrence River, agreement between United States and Canada amending agreement of May 5, 1961, effected by exchange of notes signed Washington Oct. 23, 1902 and Feb. 21, 1963; [entered into force Feb. 21, 1963, operative retroactively Oct. 15, 1962].