Belasri, Yassine, and Rachid Ellaia. “Estimation of Volatility and Correlation With Multivariate Generalized Autoregressive Conditional Heteroskedasticity Models: An Application to Moroccan Stock Markets”. International Journal of Economics and Financial Issues, vol. 7, no. 2, Apr. 2017, pp. 384-96, https://econjournals.com./index.php/ijefi/article/view/4078.