Đỗ B. Cương, N. T. Hoa, L. T. Huyền, and Đặng T. Thu, “BIOCONVERSION OF COPRA MEAL INTO PREBIOTIC MANNOOLIGOSACCHARIDES USING ENDO-β-1,4-MANNANASE PRODUCING BY ASPERGILLUS NIGER BK 01”, Vietnam J. Sci. Technol., vol. 48, no. 3, Jun. 2012.