D. K. Deady, M. J. Law Smith, M. A. Sharp and E. A. S. Al-Dujaili, “Maternal Personality and Reproductive Ambition in Women Is Associated with Salivary Testosterone Levels,” Biological Psychology, Vol. 71, 2006, pp. 29-32. http://dx.doi.org/10.1016/j.biopsycho.2005.01.009
 D. H. Baucom, P. K. Besch and S. Callahan, “Relation between Testosterone Concentration, Sex Role Identity, and Personality among Females,” Journal of Personality and Social Psychology, Vol. 48, No. 5, 1985, pp. 1218-1226. http://dx.doi.org/10.1037/0022-3522.214.171.1248
 A. Csatho, A. Osvath, E. Bicsak, K. Karadi, J. Manning and J. Kallai, “Sex Role Identity Related to the Ratio of Second to Fourth Digit Length in Women,” Biological Psychology, Vol. 62, 2003, pp. 147-156.
 T. H. Rammsayer and S. J. Troche, “Sexual Dimorphism in Second-to-Fourth Digit Ratio and Its Relation to Gender-Role Orientation in Males and Females,” Personality and Individual Differences, Vol. 42, No. 6, 2007, pp. 911-920. http://dx.doi.org/10.1016/j.paid.2006.09.002
 S. J. Troche, N. Weber, K. Hennings, C. R. Adresen and T. H. Rammsayer, “The Relationship of Digit-Ratio (2D: 4D) and Gender-Role Orientation in Four National Samples,” Journal of Individual Differences, Vol. 28, No. 2, 2007, pp. 78-87.
 M. Evardone and G. M. Alexander, “Anxiety, Sex-Linked Behaviors, and Digit Ratios (2D:4D),” Archives of Sexual Behavior, Vol. 38, No.3, 2009, pp. 442-455.
 M. Voracek, J. Pietschnig, I. W. Nader and S. Stieger, “Digit Ratio (2D:4D) and Sex-Role Orientation: Further Evidence and Meta-Analysis,” Personality and Individual Differences, Vol. 51, No. 4, 2011, pp. 417-422.
 J. Imperato-McGinley, R. E. Peterson, T. Gautier and E. Sturla, (1979) Androgens and the Evolution of MaleGender Identity among Male Pseudohermaphrodites with 5a-Reductase Deficiency,” New England Journal of Medicine, Vol. 300, pp. 1233-1237.
 J. Imperato-McGinley, R. E. Peterson, R. Stoller and W. E. Goodwin, “Male Pseudohermaphroditism Secondary to 17b-Hydroxysteroid Dehydrogenase Deficiency: Gender Role Change with Puberty,” Journal of Clinical Endocrinology and Metabolism, Vol. 49, 1979, pp. 391-395.
 B. Auyeung, S. Baron-Cohen, E. Ashwin, R. Knickmeyer, K. Taylor, G. Hackett and M. Hines, “Fetal Testosterone Predicts Sexually Differentiated Childhood Behavior in Girls and in Boys,” Psychological Science, Vol. 20, 2009, pp. 144-148.
 A. H. Heald, F. Ivison, S. G. Anderson, K. Cruickshank, I. Laing and J. M. Gibson, “Significant Ethnic Variation in Total and Free Testosterone Concentration,” Clinical Endocrinology, Vol. 58, No. 3, 2003, pp. 262-266.
 J. M. Dabbs Jr., “Salivary Testosterone Measurements: Collecting, Storing, and Mailing Saliva Samples,” Physiology and Behaviour, Vol. 49, No. 4, 1991, pp. 815-817.
 E. A. S. Al-Dujaili, “Development and Validation of a Simple and Direct ELISA Method for the Determination of Conjugated (Glucuronide) and Non-Conjugated Testosterone Excretion in Urine,” Clinica Chimica Acta, Vol. 364, No. 1-2, 2006, pp. 172-179.