Iapetus: unique surface properties and a global color dichotomy from Cassini imaging.
Denk T, Neukum G, Roatsch T, Porco CC, Burns JA, Galuba GG, Schmedemann N, Helfenstein P, Thomas PC, Wagner RJ, et al. Science. 2010 Jan 22; 327(5964):435-9. Epub 2009 Dec 10.