[1] (2014). Digest of Education Statistics. http://nces.ed.gov/programs/digest
[2] Grissmer, D. et al. (2000). Improving Student Achievement. Santa Monica: RAND.
[3] National Center for Education Statistics (2014). Conditioning Variables and Contrast Coding.
http://nces.ed.gov/nationsreportcard/pdf/main1998/2001509f.pdf
[4] Schofield, L. S., Junker, B. J., Taylor, L., & Black, D. (2014). Predictive Inference Using Latent Variables with Covariates. Psychometrika. (Forthcoming)