1. Essay on classification;Agassiz,1857
2. Size and shape in ontogeny and phylogeny;Alberch;Paleobiology,1979
3. The Pleistocene dwarf Elephants of Spinagallo;Ambrosetti;Geol. Rom.,1968
4. Entwicklungsgeschichte der Thiere: Beobachtung und Reflexion;Baer;Bornträger edit.,1828
5. Uber Darwin's Lehre;Baer,1876