Coleman, Kevin J.; Cantor, Joseph E.; Neale, Thomas H. (April 17, 2000). "Presidential Elections in the United States: A Primer"(PDF). CRS Report for Congress. Congressional Research Service - Library of Congress. p. 48. Archived(PDF) from the original on March 31, 2010. Retrieved December 24, 2016.
Coleman, Kevin J.; Cantor, Joseph E.; Neale, Thomas H. (April 17, 2000). "Presidential Elections in the United States: A Primer"(PDF). CRS Report for Congress. Congressional Research Service - Library of Congress. p. 48. Archived(PDF) from the original on March 31, 2010. Retrieved December 24, 2016.