Maddala, G.S (1977), Econometrics, New York: McGraw-Hill Book Co.
Pindyck, R.S. and Rubinfeld, D.L. (1991), Econometric Models and Economic Forecasts, Third Edition, New York: McGraw-Hill Book Co.
Theil, H. (1971), Principles of Econometrics, New York: John Wiley & Sons, Inc.