Ershova , V. B., A. V. Prokopiev, V. A. Nikishin, A. K. Khudoley, N. A. Malyshev, and A. M. Nikishin. “New Data on Upper Carboniferous - Lower Permian Deposits of Bol’shevik Island, Severnaya Zemlya Archipelago”. Polar Research, vol. 34, May 2015, doi:10.3402/polar.v34.24558.