National Park Seminary: A History by Kenneth R. Stephens
https://web.archive.org/web/20180810082202/http://operant.org/
Maryland Historical Trust
http://www.mht.maryland.gov
Montgomery County Historical Society
http://www.montgomeryhistory.org/
Montgomery County Historic Preservation
http://www.montgomeryplanning.org
National Register of Historic Places
http://www.nps.gov/nr
Preservation Maryland
http://www.preservationmaryland.org/
Silver Spring Historical Society
http://www.homestead.com/silverspringhistory/index.html
Kensington Historical Society
http://www.kensingtonhistory.org
Montgomery Preservation, Inc.
http://www.montgomerypreservation.org
National Park Service History and Culture
http://www.nps.gov/history/
National Trust for Historic Preservation
http://www.nationaltrust.org/
National Museum of Health and Medicine
http://www.medicalmuseum.mil
Homeowners/Residents of the National Park Seminary
http://www.nationalparkseminary.org