1. Aiken, L.S. and West, S.G. (1991), Multiple Regression: Testing and Interpreting Interactions, Sage Publications, Newbury Park, CA.
2. Anderson, D.R., Sweeney, D.J. and Williams, T.A. (2005), Statistics for Business and Economics, Thompson South Western, Mason, OH.
3. Andrew, W.D., Damitio, J.W. and Schmidgall, R.S. (2007), Financial Management for the Hospitality Industry, Pearson Prentice Hall, Upper Saddle River, NJ.
4. Ball, R. (1978), “Anomalies in relationships between securities' yields and yield‐surrogates”, Journal of Financial Economics, Vol. 6 Nos 2/3, pp. 103‐26.
5. Barton, S.L. (1988), “Diversification strategy and systematic risk: another look”, Academy of Management Journal, Vol. 31 No. 1, pp. 166‐75.