Jeffrey I. Mechanick et al.. “Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures – 2019 Update: Cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic and Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists.” Obesity, vol. 28, no. 4, 2020, pp. O1–O58. http://access.bl.uk/ark:/81055/vdc_100103483551.0x000014