1. P. D. Chassagne, P. Garnier, P. Mathiex-Fortunet, H. Tolerance and Long-Term Efficacy of Polyethylene Glycol 4000 (Forlax R) Compared to Lactulose in Elderly Patients with Chronic Constipation 2017 Journal of Nutrition, Health & Aging

2. Y. N. Bouhnik, C. Raskine, L. Michel, C. Riottot, M. Andrieux, C. Guillemot, F. Dyard, F. Flourie, B. Prospective, randomized, parallel-group trial to evaluate the effects of lactulose and polyethylene glycol-4000 on colonic flora in chronic idiopathic constipation 2004 Alimentary Pharmacology & Therapeutics

3. P. D. Chassagne, P. Garnier, P. Mathiex-Fortunet, H. Tolerance and long-term efficacy of polyethylene glycol 4000 (Forlax) compared to lactulose in elderly patients with chronic constipation 2017 Journal of Nutrition, Health and Aging

4. T. D. Piche, M. Comparative efficacy and safety of lactulose plus paraffin vs polyethylene glycol in functional constipation: a randomised clinical study 2020 United European Gastroenterology Journal

5. Attar A, Le´mann M, Ferguson A "Comparison of a low dose polyethylene glycol electrolyte solution with lactulose for treatment of chronic constipation" 1999 Gut