Oberzaucher, E., Katina, S., Schmehl, S. F., Holzleitner, I., Mehu-Blantar, I., & Grammer, K. (2012). The myth of hidden ovulation: Shape and texture changes in the face during the menstrual cycle. Journal of Evolutionary Psychology, 10(4), 163-175. https://doi.org/10.1556/jep.10.2012.4.1