Mode and timing of twin delivery and perinatal outcomes in low- and middle-income countries: a secondary analysis of the WHO Multicountry Survey on Maternal and Newborn Health - Ganchimeg, T; Morisaki, N; Vogel, J. P; Cecatti, J. G; Barrett, J; Jayaratne, K; Mittal, S; Ortiz-Panozo, E; Souza, João Paulo Dias de; Crowther, C; Ota, E; Mori, R (BJOG - An International Journal of Obstetrics and Gynaecology, 2014)