Cervical cancer and hormonal contraceptives: collaborative reanalysis of individual data for 16,573 women with cervical cancer and 35,509 women without cervical cancer from 24 epid... by Appleby, P, Beral, V, Berrington de González, A, Colin, D, Franceschi, S, Goodhill, A, Green, J, Peto, J, Plummer, M, Sweetland, S