YSTROM, E.; REICHBORN-KJENNERUD, T.; TAMBS, K.; MAGNUS, P.; TORGERSEN, A. M.; GUSTAVSON, K. Multiple births and maternal mental health from pregnancy to 5 years after birth: A longitudinal population-based cohort study. Norsk Epidemiologi, v. 24, n. 1-2, 29 Dec. 2014.