1. J. W. Papez, Comparative Neurology (New York: Hafner, 1967);
2. C. U. Ariens-Kappers, The Evolution of the Nervous System (Bohn: Haarlem, 1929);
3. T. L. Lentz, Primitive Nervous Systems (New Haven: Yale University Press, 1968).
4. R. Broom, Mammal-like Reptiles of South Africa and the Origin of Mammals (London: Witherby, 1932);
5. A. Brink, “Speculation on some advanced mammalian characteristics in the higher mammal-like reptiles,” Palaeontology, 4 (1956), 77–95;