Goetz, W., Leer, K., Gunnlaugsson, H. P., Bartlett, P., Basso, B., Bell, J., et al. (2008). Search for magnetic minerals in Martian rocks: Overview of the Rock Abrasion Tool (RAT) magnet investigation on Spirit and Opportunity. Journal Geophysical Research, 113(E5): E05S90. doi:10.1029/2006JE002819.