Here is one of the references: Cerebral Blood Flow and Personality: A Positron Emission Tomography Study Debra L. Johnson, Ph.D.; John S. Wiebe,et al (1990),

Here is one of the references: Cerebral Blood Flow and Personality: A Positron Emission Tomography Study Debra L. Johnson, Ph.D.; John S. Wiebe,et al (1990), The American Journal of Psychiatry, VOL. 156, No. 2 http://ajp.psychiatryonline.org/cgi/content/full/156/2/252 http://ajp.psychiatryonline.org/cgi/content/full/156/2/252 I'll try dig up the other.