Does anyone have a PDF copy of this paper and are willing to send it to me? If so, please PM me.
V. E. Ruzhentsev and M. F. Bogoslovskaya. 1971. Namurskiy etap v evolyutsii ammonoidey. Rannenamyurskie ammonoidei. Akademiya Nauk SSSR, Trudy Paleontologicheskogo Instituta 133:1-382