Maslekar, S., Waudby, P., Avery, G., Monson, J. R. T., & Duthie, G. S. (2010). Quality assurance in flexible sigmoidoscopy: Medical and nonmedical endoscopists. Surgical Endoscopy, 24(1), 89-93. https://doi.org/10.1007/s00464-009-0553-9