United States. Department of Defense. Memorandum dtd 11/09/04 for the Chief, Joint Strike Fighter Program Office from Charles Able, Principal Deputy Under Secretary of Defense (Personnel & Readiness), text, August 30, 2005; (https://digital.library.unt.edu/ark:/67531/metadc23412/m1/1/: accessed May 20, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .