Norma I. Cachola, Victoriano R. Ragasa, George B. Amano, and Reynaldo Q. Quinoy. 1993. “Chalk-Making Using Ash Wash and Plaster of Paris”. The Vector: International Journal of Emerging Science, Technology and Management (IJESTM) 2 (1). https://doi.org/10.69566/ijestm.v2i1.21.