Chemical characteristic of R chondrites in the light of P, REEs, Th and U abundances
Rahat Khan, Naoki Shirai, Mitsuru Ebihara Earth and Planetary Science Letters Volume 422, 15 July 2015, Pages 18–27 doi:10.1016/j.epsl.2015.04.008 LINK
The elemental composition of the Sun III. The heavy elements Cu to Th
Nicolas Grevesse,Pat Scott, Martin Asplund and A. Jacques Sauval Astronomy and Astrophysics 573, A27 (2015) LINK