Kozur, H. W., A. Ramovš, C.- yuan Wang, and Y. D. Zakharov. “The Importance of Hindeodus Parvus (Conodonta) for the Definition of the Permian-Triassic Boundary and Evaluation of the Proposed Sections for a Global Stratotype Section and Point (GSSP) for the Base of the Triassic”. Geologija, vol. 37, no. 1, Dec. 1994, pp. 173-1, doi:10.5474/geologija.1995.007.