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 (Dec. 1993). DOI:https://doi.org/10.69566/ijestm.v2i1.21.