Suharyatun, Siti, et al. “Improving The Growth and Yield of Pak Choy (Brassica Chinensis L.) Using Cacao Pod Husk Biochar”. International Journal on Advanced Science, Engineering and Information Technology, vol. 14, no. 2, Apr. 2024, pp. 777-85, doi:10.18517/ijaseit.14.2.19536.