Ngoc Oanh, H., and T. Ngoc Hung. “PURIFICATION OF PECTINASE FROM ASP.NIGER BY THE TECHNIQUES OF GEL FILTRATION AND CROSS-FLOW MEMBRANE”. Science and Technology Development Journal, Vol. 11, no. 8, Aug. 2008, pp. 46-50, doi:https://doi.org/10.32508/stdj.v11i8.2673.