1. Chaikin A (1995) A man on the moon: the voyages of the Apollo astronauts. Penguin Books
2. Dubbs C, Paat-Dahlstrom E (2011) Realiing tomorrow: the path to private spaceflight. University of Nebraska Press
3. Friedman L (2015) From human spaceflight mars to the stars. University of Arizona Press
4. Launius R (2013) Exploring the solar system: the history and science of planetary exploration. Palgrave Macmillan
5. Laurini K et al (2015) The global exploration roadmap and expanding human/robotic exploration mission collaboration opportunities, Jerusalem, Israel: IAC-15-A3.1.1