Bessell, M.S.; Castelli, F.; Plez, B. (1998). "Model atmospheres broad-band colors, bolometric corrections and temperature calibrations for O–M stars". Astronomy and Astrophysics333: 231–250. Bibcode:1998A&A...333..231B.
http://www.solarviews.com/eng/solarsys.htmArquivado 02 de maio de 2007 en Wayback Machine. ; The Solar System, acceso 8 de maio de 2009 en Solarviews.com: "The planets, most of the satellites of the planets and the asteroids revolve around the Sun in the same direction, in nearly circular orbits"
http://www.solarviews.com/eng/solarsys.htmArquivado 02 de maio de 2007 en Wayback Machine. ; The Solar System, acceso 8 de maio de 2009 en Solarviews.com: "The planets, most of the satellites of the planets and the asteroids revolve around the Sun in the same direction, in nearly circular orbits"