1. Uber Entwickelungsgeschichte der Thiere: Beobachtung und Reflektion;von Baer,1828
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3. Haeckel's ABC of Evolution and Development;Richardson;Biol. Rev.,2002
4. On the law of development commonly known as von Baer's Law; and on the significance of ancestral rudiments in embryonic development;Sedgwick;Q. J. Microsc. Sci.,1894
5. On the validity of von Baer's laws in evolutionary morphology;Slaby;Folia Morphol. (Praha),1990