Ferrero S, Remorgida V, Venturini PL, Leone Roberti Maggiore U. Norethisterone acetate versus norethisterone acetate combined with letrozole for the treatment of ovarian endometriotic cysts: a patient preference study. Eur J Obstet Gynecol Reprod Biol 2014;174:117-122.
https://www.ejog.org/article/S0301-2115(13)00618-0/fulltext