Huitema, B. E. (2011). Analysis of covariance and alternatives: Statistical methods for experiments, quasi-experiments, and single-case studies (2nd ed.). Wiley.

Huitema, Bradley E. Analysis of Covariance and Alternatives: Statistical Methods for Experiments, Quasi-experiments, and Single-case Studies. 2nd ed. Hoboken, N.J.: Wiley, 2011.

Huitema, Bradley E. Analysis of Covariance and Alternatives: Statistical Methods for Experiments, Quasi-experiments, and Single-case Studies. 2nd ed. Wiley, 2011.