1. T.F. Rogers, Space tourism—its importance, its history, and a recent extraordinary development, in: Proceedings of the 13th Humans In Space (HIS) Symposium, Fira, Santorini, Greece, 20–25 May 2000.
2. D.Webber, Space tourism: its history, future and importance, in: Proceedings of the 2nd International IAA Symposium on Private Human Access to Space (PHAS), Arcachon, 30 May–1 June 2011; see also Acta Astronautica, 92, No. 2, 2013, 138–143.
3. From Spirit of St. Louis to SpaceShipTwo: a study on the challenge of future space tourism development;Chang;J. Aeronaut. Astronaut. Aviat.,2013
4. Vacationing in space: tourism seeks ‘new skies’;Laing,2004
5. Space Tourism Market Study: Orbital Space Travel & Destinations With Suborbital Space Travel;Beard,2002