Orchard M. J. “Lower Triassic Conodonts from the Canadian Arctic, Their Intercalibration With Ammonoid-Based Stages and a Comparison With Other North American Olenekian Faunas”. Polar Research, vol. 27, no. 3, Dec. 2008, pp. 393-12, doi:10.3402/polar.v27i3.6187.