1. Multiple Regression: Testing and Interpreting Interaction;Aitken,1996
2. Conditioning Diagnosis, Collinearity and Weak Data in Regression;Belsley,1991
3. Regression Analysis by Example;Chatterjee,2012
4. Applied Regression Analysis;Draper,1998
5. Generalized collinearity diagnostics;Fox;J. Stat. Assoc.,1992