Andersen, T.G. and Bollerslev, T. (1997), “Intraday Periodicity and Volatility Persistence in Financial Markets,” Journal of Empirical Finance, Vol. 4, pp. 115-118.
Andersen, T.G. and Bollerslev, T. (1997), “Heterogeneous Information Arrivals and Return Volatility Dynamics: Uncovering the Long-Run in High Frequency Returns,” Journal of Finance, Vol. 52, pp. 975-1005.