Roberts, H., Dahl, P., Kelley, S., & Frei, R. (2002). New Pb–Pb and Ar–Ar Ages from SW Montana, USA: Constraints on the Proterozoic and Archæan Tectonic and Depositional History of the Wyoming Province. Precambrian Research. https://doi.org/10.1016/S0301-9268(02)00076-1
Roberts, H, Peter Dahl, S Kelley, and Robert Frei. 2002. “New Pb–Pb and Ar–Ar Ages from SW Montana, USA: Constraints on the Proterozoic and Archæan Tectonic and Depositional History of the Wyoming Province”. Precambrian Research. https://doi.org/10.1016/S0301-9268(02)00076-1.
Roberts, H., P. Dahl, S. Kelley, and R. Frei. New Pb–Pb and Ar–Ar Ages from SW Montana, USA: Constraints on the Proterozoic and Archæan Tectonic and Depositional History of the Wyoming Province. Precambrian Research, 31 July 2002, doi:10.1016/S0301-9268(02)00076-1.