1. Feasibility of rocket propellant production on Mars
2. Drake,Bret(editor), NASA/SP-6107-ADD -ReferenceMission Version 3.0, AddendumtotheHuman Exploration ofMars:TheReferenceMission oftheNASAMarsExploration StudyTeam‖,June1998.
3. Press Release,NASA PhoenixMarsLander Confirms Frozen Water‖, June20,2008, http://phoenix.lpl.arizona.edu/06_20_pr.php