1. Abramowitz, M., Stegun, I.A., 1972. Handbook of Mathematical Functions. National Bureau of Standards, Washington, D.C.
2. The American Petroleum Institute, 1997. Basic Petroleum Data Book XVIII.
3. Heteroskedasticity and auto correlation consistent covariance matrix estimation;Andrews;Econometrica,1991
4. Futures-trading activity and stock price volatility;Bessembinder;J. Finance,1992
5. Price volatility, trading volume, and market depth: Evidence from futures markets;Bessembinder;J. Fin. Quantit. Anal.,1993