1. Fix, M.E. and Passel, J.S. US Immigration at the Beginning of the 21st Century. Testimony before the Subcommittee on Immigration and Claims Hearing on The US Population and Immigration. Committee on the Judiciary. Washington, DC: US House of Representatives. retrieved Sept 26, 2002 from http://www.urban.org/urlprint. cfm?ID=7321
2. Current Population Reports, Series P23-206;Schmidley A.D.,2001