Frisch, T., S. Kolaric, and D. Schiereck. “Returns On Large Stock Price Declines And Increases In The South African Stock Market: A Note On Market Efficiency”. International Business & Economics Research Journal (IBER), vol. 13, no. 3, Apr. 2014, pp. 581-92, doi:10.19030/iber.v13i3.8595.