Citalopram in premenstrual dysphoria: is intermittent treatment during luteal phases more effective than continuous medication throughout the menstrual cycle? - Wikander,I.; Sundblad,C.; Andersch,B.; Dagnell,I.; Zylbertein,D.; Bengtsson,F.; Eriksson,E. (J Clin Psychopharmacol, 1998)