Rockwood NJ, Jeon M. Estimating complex measurement and growth models using the R package PLmixed. Multivar Behav Res. 2019 Mar;54(2):288-306. doi: 10.1080/00273171.2018.1516541
Pueschel SM, Rothman KJ, Ogilby JD. Birth weight of children with down's syndrome. Am J Ment Defic. 1976 Jan;80(4):442-5.