Okoński, S. P., Z. Górny, M. Bąk, and K. Bąk. “Lithistid Spicules in the Sediments of the Turonian Variegated Shale in the Silesian Nappe, Polish Outer Carpathians”. Geology, Geophysics and Environment, vol. 40, no. 1, Mar. 2014, p. 33, doi:10.7494/geol.2014.39.1.33.