1. Szalay, F. S. & Delson, E. Evolutionary History of the Primates (Academic, New York, 1979).
2. Beard, K. C. Nature 345, 340–341 (1990).
3. Kay, R. F., Thorington, R. W. & Houde, P. Nature 345, 342–344 (1990).
4. Martin, R. D. Nature 345, 291–292 (1990).
5. Beard, K. C. Postcranial Anatomy, Locomotor Adaptations, and Paleoecology of Early Cenozoic Plesiadapidae, Paromomyidae and Micromomyidae (Eutheria, Dermoptera) (Johns Hopkins University, Baltimore, 1989).