Lasser RB, et al. : The role of intestinal gas in functional abdominal pain. N Engl J Med, Vol.293, p.524, 1975
Tomlin J, et al. : Investigation of normal flatus production in healthy volunteers. Gut, Vol32, p.665, 1991
Maddock WG, et al. : Gastrointestinal gas. Observations on belching during anesthesia, operations and pyelography and rapid passage of gas. Ann Surg, Vol.130, p.512, 1949