1. Belsley, D. A. (1984). Demeaning conditioning diagnostics through centering (with discussion). The American Statistician, 38, 73–77.
2. Belsley, D. A. (1991). Collinearity diagnostics: Collinearity and weak data in regression. New York: Wiley.
3. Belsley, D. A., Kuh, E., & Welsch, R. E. (1980). Regression diagnostics: Identifying influential data and sources of collinearity. New York: Wiley.
4. Christensen, R. (2015). Analysis of variance, design, and regression: Linear modeling for unbalanced data (2nd ed.). Boca Raton, FL: Chapman and Hall/CRC Press.
5. Christensen, R. (2018). Comment on “A note on collinearity diagnostics and centering” by Velilla (2018). The American Statistician, 72, 114–117.