www.814thcds.com

http://www.814thcds.com/814th-and-the-notch.htm

Anchor text: 814th Combat Defense Squadron - Air Police squadron that guarded "The Notch"

Wikipedia: Post-Attack Command and Control System Facility, Hadley

http://www.814thcds.com/entrance-to-the-notch.jpg

Anchor text: A 1990s era photo of the entrance

Wikipedia: Post-Attack Command and Control System Facility, Hadley