Häntzschel, W. (1962). Trace fossils and Problematica. In Treatise on Invertebrate Paleontology, Part W., Edited by: Moore, R. C. W177–W245. New York and Lawrence: Geological Society of America and University of Kansas.
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Häntzschel, W.
1962
Trace fossils and Problematica. In Treatise on Invertebrate Paleontology, Part W., Edited by: Moore, R. C. W177–W245. New York and Lawrence: Geological Society of America and University of Kansas.