Boynton, W. V., d'Uston, C., Arnold, J. R., Trombka, J. I., Feldman, W. C., Mitrofanov, I., Englert, P. A. J., Metzger, A.
E., Reedy, R. C., Squyres, S. W., Wänke, H., Bailey, S. H., Brückner, J., Evans, L. G., Starr, R., & Fellows, C. W. (1999). Scientific investigations on the elemental composition of Mars by means of the Mars
Surveyor 2001 gamma-ray spectrometer. In Lunar and Planetary Science XXX. Houston: Lunar
and Planetary Institute.