1. AstroGrasp
2. The Importance of Astronomy is Modern Education;Evry L.;Annals of the New York Academy of Sciences,1972
3. John R. Percy Erindale Campus and Department of Astronomy. 2006. Teaching Astronomy: Why and How? University of Toronto Mississauga Ontario Canada L5L 1C6 http://www.aavso.org/files/webpublications/ejaavso/v35n1/248.pdf John R. Percy Erindale Campus and Department of Astronomy. 2006. Teaching Astronomy: Why and How? University of Toronto Mississauga Ontario Canada L5L 1C6 http://www.aavso.org/files/webpublications/ejaavso/v35n1/248.pdf
4. Tangible avatar and tangible earth