Johannes CB, Crawford SL. Menstrual bleeding, hormones, and the menopausal transition. Semin Reprod Endocrinol. 1999 Jan 1;17(4):299-309.
Campo R, Brullet E, Montserrat A, Calvet X, Rivero E, Brotons C. Topical pharyngeal anesthesia improves tolerance of upper gastrointestinal endoscopy: a randomized double-blind study. Endoscopy. 1995 Nov;27(9):659-64.