KahnH., & SemposC. (1989). Statistical methods in epidemiology. New York, NY: Oxford University Press, 51–58.
2.
KnappT. R., & SchaferW. D. (2009). From Gain Score t to ANCOVA F (and vice versa). Practical Assessment, Research & Evaluation, 14(6). Retrieved from http://pareonline.net/getvn.asp?v=14&n=6
3.
SheskinD.2000. Handbook of parametric and nonparametric statistical procedures. Boca Raton, FL: CRC Press.