Columbia subject headings:
Aerial reconnaissance.
SR-71 Blackbird (Jet reconnaissance plane)
U-2 (Reconnaissance aircraft)
United States. Air Force. Strategic Reconnaissance Squadron, 99th.
Harvard subject headings:
Aerial reconnaissance, American.
Aerial reconnaissance.
SR-71 (Jet reconnaissance plane)
SR-71 Blackbird (Jet reconnaissance plane)
U-2 (Reconnaissance aircraft)
United States. Air Force. Squadron, 99th.
United States. Air Force. Strategic Reconnaissance Squadron, 99th.
Princeton subject headings: