1. NASA, The vision for space exploration, 2004, 〈http://www.nasa.gov/pdf/55583main_vision_space_exploration2.pdf〉
2. ESA, Aurora Programme: Executive Summary, 2003, 〈http://esamultimedia.esa.int/docs/Au-roraProgrammeExecutiveSummary.pdf〉.
3. NASA, ESMD Internal White Paper: Concept Proposal: Generation Mars, 2009.
4. Open Space: a Citizen’s Jury on Space Exploration;Safwat,2006
5. Space education: a step forward;Ottavianelli;Space Policy,2002