<cite class="book" style="font-style:normal">Roger D. Launius (July 1994)      <i> Apollo: A Retrospective Analysis</i>, Monographs in Aerospace History, No. 3, NASA  <small>SP-2015-4503</small></cite>
NASA/Roger D. Launius
<a rel="nofollow" class="external free" href="https://history.nasa.gov/monograph3.pdf">https://history.nasa.gov/monograph3.pdf</a>