1. COSPAR, Planetary Protection Policy, October 2002, as amended, March 2005 〈http://www.cosparhq.org/scistr/PPPolicy.htm〉.
2. National Aeronautics and Space Administration, Planetary Protection Provisions for Robotic Extraterrestrial Missions, NPR 8020.12C, Washington, DC, 2005.
3. Space Studies Board, US National Research Council, Preventing the Forward Contamination of Mars, National Academy Press, Washington, DC, 2005.
4. D.W. Beaty, K.L. Buxbaum, M.A. Meyer, N.G. Barlow, W.V. Boynton, B.C. Clark, J.W. Deming, P.T. Doran, K.S. Edgett, S.L. Hancock, J.W. Head, M.H. Hecht, V. Hipkin, T.L. Kieft, R.L. Mancinelli, E.V. McDonald, C.P. McKay, M.T. Mellon, H. Newsom, G.G. Ori, D.A. Paige, A.C. Schuerger, M.L. Sogin, J.A. Spry, A. Steele, K.L. Tanaka, M.A. Voytek, Findings of the Mars Special Regions Science Analysis Group, Unpublished white paper, p. 76, posted June 2006 by the Mars Exploration Program Analysis Group (MEPAG) at 〈http://mepag.jpl.nasa.gov/reports/index.html〉.
5. MEGIS Participants, Report of the Mars Environmental GIS (MEGIS) Workshop, October 5–6, 2005, Unpublished report file posted by the Mars Exploration Program Analysis Group (MEPAG) at 〈http://mepag.jpl.nasa.gov/workshop/index.html〉.