Top: Gettysburg, July 2, 1863. Gettysburg, PA: Stan Clark Military Books, 1992. . First published 1913 by Neale Publishing Co. Petruzzi, J. David, and Steven Stanley. The Complete Gettysburg Guide. New York: Savas Beatie, 2009. . Pullen, John J. (1957), The Twentieth Maine: A Volunteer Regiment in the Civil War, Philadelphia: Lippencott, OCLC 475760 . External links Hills of Pennsylvania Gettysburg Battlefield Gettysburg National Military Park Landforms of Adams County, Pennsylvania Historic district contributing properties in Pennsylvania