Reflex cytology for triage of high-risk human papillomavirus positive self-sampled material in cervical cancer screening: a prospective cohort study. - Loopik DL; Melchers W; Vedder J; van den Brule A; Massuger L; Bekkers R; Siebers AG (BJOG : an international journal of obstetrics and gynaecology, 2020)