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Torvik FA, Ystrom E, Czajkowski N, Tambs K, Røysamb E, Ørstavik R, Knudsen GP, Kendler KS, Reichborn-Kjennerud T.Torvik FA, et al. Among authors: tambs k.BMC Public Health. 2015 Feb 12;15:134. doi: 10.1186/s12889-015-1457-3.BMC Public Health. 2015.PMID: 25884296Free PMC article.