Ultrastructural studies on graptofites - Urbanek, Adam 1928-2014; Towe, Kenneth M. (Washington : Smithsonian Institution Press, 1974)
Contenido: v. 1. The periderm and its derivatives in the Dentroidea and in Mastigograptus.--v. 2. The Periderm and its derivatives in the Graptoloidea.
En: Smithsonian contributions to paleobiology. No. 1- Washington : Smithsonian Institution Press 1969- , no. 20, 22.
Keywords: VERTEBRADOS FOSILES; PALEOBIOLOGIA -- ORDOVICIO