1. Bailey, A., LeCouteur, A., Gottesman, I., Bolton, P., Simonoff, E., Yuzda, E., et al. (1995). Autism as a strongly genetic disorder: Evidence from a British twin study. Psychological Medicine, 25, 63–77.
2. Benirschke, K., Kaufmann, P., & Baergen, R. (2006). Pathology of the Human Placenta (5th Edition), Springer Science+Business Media Inc., New York 877–885. (Note that the 2:1 ratio for MZ-MC/MZ-DC is for the US population, and is different for some other ethnic/racial groups).
3. Blickstein, I. (2006). Monozygosity. In A. Kurjak & F. A. Chervenak (Eds.), Textbook of Perinatal Medicine, v2, (2nd edition) Chap. 146, Informa UK Ltd. Boca Raton, FL: Taylor & Francis.
4. Bohm, H. V., Fry McComish, J. E., & Stewart, M. G. (2007). On a possible early identification procedure for babies at high risk for autistic spectrum disorder. Medical hypotheses, 69, 47–51. doi: 10.1016/j.mehy.2006.09.073 .
5. Gilbert-Barness, E., & Debich-Spicer, D. (2004). Embryo and Fetal Pathology. Chap. 23, (p. 622). Cambridge, UK, New York: Cambridge University Press.