1. Baker, John R. 1949. “The Cell-Theory: A Restatement, History, and Critique, Part II.” Quarterly Journal of Microscopical Science 90(9): 87–108
2. Baker, John R. 1952. “The Cell-Theory: A Restatement, History, and Critique Part III. The Cell as a Morphological Unit .” Quarterly Journal of Microscopical Science 93(22): 157–190
3. Brain, Robert. 2015. The Pulse of Modernism: Physiological Aesthetics in Fin-de-Siècle Europe. Seattle: University of Washington Press.
4. Churchill, Frederick B. 1989. “The Guts of the Matter: Infusoria from Ehrenberg to Bütschli, 1838–1876.” Journal of the History of Biology 22(2): 189–213.
5. Cohn, Ferdinand. 1850. “Nachträge zur Naturgeschichte des Protococcus Pluvialis Kützing.” Novorum Actorum Academiae Caesareae Leopoldino-Carolinae Naturae Curiosorum 22: 605–764.