1. “Seeking a Human Spaceflight Program Worthy of a Great Nation,” Review of U.S. Human Spaceflight Plans Committee, Washington, D.C. Oct. 2009, http://www.nasa.gov/pdf/617036main_396093main_HSF_Cmte_FinalReport.pdf.
2. DrakeB. G. “Human Exploration of Mars Design Reference Architecture 5.0 (and Addendum),” NASA SP-2009-566, July 2009.
3. DrakeB. G. “Human Exploration of Mars Design Reference Architecture 5.0 Addendum #2,” NASA SP-2009-566-ADD2, March 2014.