1. Alberti, H., Groos-Uffenorde, H., Streel, M., Uffenorde, H., & Walliser, O. H. (1974). The stratigraphic significance of the Protognathodus fauna from Stockum (Devonian/Carboniferous boundary, Rhenish Schiefergebirge). Newsletters on Stratigraphy, 3, 263–276.
2. Aristov, V. A. (1988). Devonian conodonts of the central Devonian field (Russian Platform). Academy of Sciences of the USSR, Transactions, 432, 1–119 [in Russian].
3. Bahrami, A., Corradini, C., & Yazdi, M. (2011). Upper Devonian-Lower Carboniferous conodont biostratigraphy in the Shotori Range, Tabas area, Central-East Iran Microplate. Bolletino della Società Paleontologica Italiana, 50, 35–53.
4. Becker, R. T. (1996). New faunal records and holostratigraphic correlation of the Hasselbachtal D/C-boundary auxiliary stratotype (Germany). Annales de la Société géologique de Belgique, 117, 19–45.
5. Becker, R. T. (2000). Taxonomy, evolutionary history, and distribution of the middle to late Famennian Wocklumeriina (Ammonoidea, Clymeniida). Mitteilungen aus dem Museum für Naturkunde in Berlin, Geowissenschaftliche Reihe, 3, 27–75.