Khan, A., S. Sahay, and N. Rai. “Production and Optimization of Pectinase Enzyme Using <em>Aspergillus niger</em> Strains in Solid State Fermentation”. Research in Biotechnology, vol. 3, no. 3, May 2012, https://updatepublishing.com/journal/index.php/rib/article/view/2405.