Weis, D., B. Kieffer, D. Hanano, I. Nobre Silva, J. Barling, W. Pretorius, C. Maerschalk, and N. Mattielli 2007. Hf isotope compositions of U.S. Geological Survey reference materials, Geochem Geophys. Geosyst., 8, Q06006, doi:10.1029/2006GC001473.

Weis, D., B. Kieffer, D. Hanano, I. Nobre Silva, J. Barling, W. Pretorius, C. Maerschalk, and N. Mattielli 2007. Hf isotope compositions of U.S. Geological Survey reference materials, Geochem Geophys. Geosyst., 8, Q06006, doi:10.1029/2006GC001473.