Δριτσάκης Ν., Κάπαρης Α., and Τζιλιλής Δ. “An Index of Efficiency for the Athens Stock Exchange”. SPOUDAI Journal of Economics and Business, vol. 53, no. 3, July 2003, pp. 37-56, https://spoudai.org/index.php/journal/article/view/437.