Goyal, R., R. K. Narula, and M. K. Jindal. “Hybrid Binarization Approach for Typewritten Gurmukhi Script Documents”. International Journal of Control and Automation, Vol. 12, no. 4, Oct. 2019, pp. 194 -98, https://sersc.org/journals/index.php/IJCA/article/view/1113.