Meriwether Lewis (2012). “History of the Expedition under the Command of Captains Lewis and Clark, Vol. I. To the Sources of the Missouri, Thence Across the Rocky Mountains and Down the River Columbia to the Pacific Ocean. Performed During the Years 1804-5-6.”, p.229, tredition
David Ricardo, John Ramsay McCulloch (1852). “The Works of David Ricardo. With a notice of the life and writings of the author: by J. R. McCulloch”, p.373