Pattarapaprakorn, Woraratana, Makoto Tono, and Hiro Niyama. 2004. “A Proposed Surface Area Measurement Module for Rural Folks: Desing Concept and Trial Setup”. ASEAN Journal of Chemical Engineering 4 (1), 25-32. https://journal.ugm.ac.id/v3/AJChE/article/view/7584.