Basoglu, M. S., T. Korkmaz, and E. I. Cevik. “London Metal Exchange: Causality Relationship Between the Price Series of Non-Ferrous Metal Contracts”. International Journal of Economics and Financial Issues, vol. 4, no. 4, Aug. 2014, pp. 726-34, https://www.econjournals.com/index.php/ijefi/article/view/875.