References: http://emedicine.medscape.com/article/175667-overview http://emedicine.medscape.com/article/171886-overview Liddle, Rodger A., et al. “Cholecystokinin bioactivity in human plasma. Molecular forms, responses to feeding, and relationship to gallbladder contraction.” Journal of Clinical Investigation 75.4 (1985): 1144. Stampfer, Meir J., et al. “Risk of symptomatic gallstones in women with severe obesity.” The American journal of clinical nutrition 55.3 (1992): 652-658.