Brückner, J., Gellert, R., Clark, B. C., Dreibus, G., Lugmair, G., Klingelhöfer, G., et al. (2006). Two years of chemical sampling in Meridiani Planum by the APXS on board the Mars Exploration Rover Opportunity. In Lunar and Planetary Science XXXVII. Houston: Lunar and Planetary Institute.