Reference

N. Weissenfels, Erich Scholtyseck, Rolf Entzeroth (1989): Electron Microscope Study of an Intranuclear Protozoan Parasite in Archaeocytes of the Fresh Water Sponge Ephydatia fluviatilis L. (Porifera) – Archiv für Protistenkunde – 137_1989: 247 - 253.