Literature
- Olson, E. C. 1971. Vertebrate Paleontology, Wiley Interscience, New York.
- Parker, S. B. 1982. Synopsis and classification of living organism. McGraw-Hill, New York.
- Romer, A. S. and Parsons, T. S. 1977. The vertebrate body , 5th ed. Saunders, Philadelphia.
- Starck, D. 1978. Vergleichende Anatomic der Wirbeltiere, 3 vols., Springer, Berlin and Heidelberg.
- Young, J. Z. 1957. The Life of Mammals, Oxford University Press, London.
- Young, J. Z. 1981. The life of vertebrates, 3d ed. Oxford University Press, New York.