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
Doward LC, McKenna SP, Meads DM, Jovell AJ, Fisk J, Eckert BJ. The international development of patient reported outcome indices for multiple sclerosis. Poster presented at the 2006 Sixteenth Meeting of the European Neurological Society; May 2006. Lausanne, Switzerland. [abstract] J Neurol. 2006; 253(Suppl 2):125.