1998, Emily M. Haymes & Priscilla M. Clarkson, "Minerals and Trace Minerals", in Nutrition for Sport and Exercise (eds. Jacqueline R. Berning & Suzanne Nelson Steen), Aspen Publishers (1998), ISBN 9780834208827, page 80:Runners with amenorrhea experience more running-related injuries than runners with eumenorrhea, and an increased incidence of stress fractures.
2010, Marc A. Fritz & Leon Speroff, Clinical Gynecologic Endocrinology and Infertility, Wolters Kluwer Health (2010), ISBN 9780781779685, page 514:The prevalence of eumenorrhea among women with PCOS is significantly increased if the Rotterdam diagnostic criteria are applied, because hirsute eumenorrheic women with polycystic ovaries are included.
2013, Anne B. Loucks, "Menstruation Function and Dysfunction in the Female Athlete", in Nutrition and the Female Athlete: From Research to Practice (ed. Katherine A. Beals), CRC Press (2013), ISBN 9781439849385, page 208:In eumenorrhea, menstrual cycles occur at intervals of 25 to 35 days.
