Samarium Isotopic Constraints for an Early Compaction Age of Northwest Africa 7533
M. Humayun, H. Hidaka, S. Yoneda, C. Göpel, B. Zanda, R. H. Hewins 47th Lunar and Planetary Science Conference (2016), Abstract #1725 PDF
Pb-isotopic evidence for an early, enriched crust on Mars
J.J. Bellucci, A.A. Nemchin, M.J. Whitehouse, M. Humayun, R. Hewins, B. Zanda Earth and Planetary Science Letters Volume 410, 15 January 2015, Pages 34–41 available online 2 December 2014 LINK (open access)
Planetary science: A chunk of ancient Mars
McSween H.Y. Nature 503, 473–474 (28 November 2013) doi:10.1038/nature12836 LINK