1. U.S. Senate. Passengers Arriving in the United States during the Year Ending December 31, 1856. Senate Executive Document 54, 34th Cong., 3rd sess., 1857.
2. U.S. House of Representatives. Passengers Arriving in the United States (1852). House Executive Document 45, 32nd Cong., 2nd sess., 1853.
3. Business Cycles