Maternal weight gain patterns and birth weight outcome in twin gestation Lantz, M.E.; Chez, R.A.; Rodriguez, A.; Porter, K.B. Obstetrics and Gynecology 87(4): 551-556 1996 0029-7844 10.1016/0029-7844(95)00485-8 https://eurekamag.com/research/008/995/008995799.php