N. Aini Sulaiman, L. Kheng Oon, N. Muhammad Mahadi, and N. Zazarina Ramly, “Optimization of Alkaline Protease Production by Alkaliphilic Bacillus lehensis G1 using Statistical Design”, IJET, vol. 7, no. 4.38, pp. 1651–1654, Dec. 2018, doi: 10.14419/ijet.v7i4.38.29225.