Axtell, R.W. 1958. A monographic revision of the iguanid genus Holbrookia. Ph.D. Thesis, University of Texas, Austin.
Bush, G.L. 1969. Sympatric host race formation and speciation in frugivorous flies of the genus Rhagoletis (Diptera, Tephritidae) . Evolution 23: 237-51.
____. 1975. Modes of animal speciation. Ann. Rev. Ecol. Syst. 6:339-364.
Dobzhansky, T. 1937. Genetics and the Origin of Species [1st ed.]. Columbia University Press, New York.
Ehrlich, P.R. and P.H. Raven. 1969. Differentiation of populations. Science 165:1228-32.
Endler, J.A. 1973. Gene flow and population differentiation. Science 179:243-50.
____. 1977. Geographic Variation, Speciation, and Clines. Monogr. Popl. Biol. 10. Princeton University Press, Princeton, N.J.
Hall, W.P. 1973. Comparative population cytogenetics, speciation, and evolution of the iguanid lizard genus Sceloporus. Ph.D. Thesis, Harvard University Cambridge, Mass.
____. 1977. Cascading chromosomal speciation and the paradoxical role of contact hybridization as a barrier to gene flow. Informally published, 91 pp.
____ and R.K. Selander. 1973. Hybridization of karyotypically differentiated populations in the Sceloporus grammicus complex (Iguanidae) . Evolution 27:226-42.
Hempel, C.G. 1965. Aspects of Scientific Explanation and Other Essays in the Philosophy of Science. The Free Press, New York.
Huxley, J.S. [ed.]. 1940. The New Systematics. Clarendon Press, Oxford.
____. 1942. Evolution, the Modern Synthesis. Alien and Unwin, London.
Kuhn, T.S. 1962. The Structure of Scientific Revolutions. University of Chicago Press, Chicago.
____. 1970a. Logic of discovery of psychology of research, pp. 1-23 in Lakatos and Musgrave, eds. (1970).
____. 1970b. Reflections on my critics, pp. 231-78 in Lakatos and Musgrave, eds. (1970).
____. 1970c. Postscript--1969, pp. 174-210 in T.S. Kuhn, The Structure of Scientific Revolutions, Enlarged Ed. University of Chicago Press, Chicago.
____. 1977. Second thoughts on paradigms, pp. 459-482 in Suppe, ed. (1977).
Lakatos, I. and A. Musgrave, eds. 1970. Criticism and the Growth of Knowledge. Cambridge University Press, Cambridge.
Masterman, M. 1970. The nature of a paradigm, pp. 59-90 in Lakatos and Musgrave, eds. (1970).
Mayr, E. 1942. Systematics and the Origin of Species. Columbia University Press, New York.
Norris, K.S. 1958. The evolution and systematics of the iguanid genus Uma and its relation to the evolution of other North American desert reptiles. Bull. Amer. Mus. Nat. Hist. 114: 247-326.
Popper, K.R. 1934. Logik der Forschung. Julius Springer Verlag, Vienna.
____. 1959 [1972--6th Impression, Revised]. The Logic of Scientific Discovery. Hutchinson & Co., London.
____. 1963 [1972--4th Edition, Revised]. Conjectures and Refutations: The Growth of Scientific Knowledge. Routledge & Kegan Paull, London.
____. 1966a. The Open Society and its Enemies. Vol. 1. The Spell of Plato. 5th Ed., Revised. Routledge & Kegan Paull, London.
____. 1966b. The Open Society and its Enemies. Vol. 2. The High Tide of Prophecy: Hegel, Marx, and the Aftermath. 5th Ed., Revised. Routledge & Kegan Paull, London.
____. 1972. Objective Knowledge, An Evolutionary Approach. Oxford University Press, London.
____. 1976. Unended Quest: An Intellectual Autobiography. Open Court Publ. Co., La Salle, I11.
Simpson, G.G. 1944. Tempo and Mode in Evolution. Columbia University Press, New York.
Sokal, R.R. 1973. The species problem reconsidered. Syst. Zool. 22:360-74.
Stebbins, G.L. 1950. Variation and Evolution in Plants. Columbia University Press,) New York.
Suppe, F. 1977. The Structure of Scientific Theories, 2nd Ed: Edited with a Critical Introduction and an Afterword. University of Illinois Press, Urbana.
Todd, N.B. 1970. Karyological fissioning and canid phylogeny. J. Theor. Biol. 26:445-80.
White, M.J.D. 1945. Animal Cytology and Evolution [1st. Ed.]. Cambridge University Press, London.
____. 1968. Models of speciation. Science 159:1065-70.
____. 1978. Modes of Speciation. W.A. Freeman and Co., San Francisco.
Wilson, A.C., G.L. Bush, S.M. Case, and M.-C. King. 1975. Social structuring of mammalian populations and rate of chromosomal evolution. Proc. Nat. Acad. Sci. USA 72:5061-5.