konecne - http://ekonomika.etrend.sk/svet/cia-priznala-existenciu-zahadnej-oblasti-51-v-nevadskej-pusti.html

zrejmy zdroj - http://www2.gwu.edu/~nsarchiv/NSAEBB/NSAEBB434/

inspiracia pre ministrov obrany - Through the use of "unvouchered" funds — virtually free from any external oversight or accounting — the CIA could write checks to finance secret programs, such as the U-2. As it turned out, Lockheed produced the 20 aircraft at a total of $18,977,597 (including $1.9 million in profit), or less than $1 million per plane. It was all "under budget," a miracle in today's defense contracting world.