Karl E. Karlstrom u. a.: Redefining the Tonto Group of Grand Canyon and recalibrating the Cambrian timescale. In: Geology. volume 48, number 5, 2020, S.425–430, doi:10.1130/G46755.1.
C. R. Fenton, R. J. Poreda, B. P. Nash, R. H. Webb, T. E. Cerling: Geochemical discrimination of five Pleistocene lava-dam outburst-flood deposits, western Grand Canyon, Arizona. In: The Journal of Geology. Vol. 112, 2004, S. 91–110, doi:10.1086/379694.