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Hubbs-Tait L, Page MC, Huey EL, Starost HJ, Culp AM, Culp RE, Harper ME.Hubbs-Tait L, et al.Early Child Res Q. 2006 Oct 1;21(4):491-506. doi: 10.1016/j.ecresq.2006.09.002.Early Child Res Q. 2006.PMID: 19629192Free PMC article.