Niedźwiedzki, Robert, Dawid Surmik, Agnieszka Chećko, and Mariusz A Salamon. 2021. “A Regurgitalite of the Middle Triassic (Muschelkalk) from Upper Silesia (Poland)”. Geology, Geophysics and Environment 47 (1):33-40. https://doi.org/10.7494/geol.2021.47.1.33.