Moore, J. M.; Spenser, J. R.; Mckinnon, W. B.; Beyer, R. A. (Apr 10, 2017). "The Geology of Charon as Revealed by New Horizons". International Asteroids, Comets, Meteors (ACM) Conference 2017. LUNAR AND PLANETARY SCIENCE AND EXPLORATION. Retrieved 3 April 2018.