Ola, P., and E. Taus. “USE OF SEQUENT ADSORPTION WITH ACTIVATED NATURAL ZEOLITE AND ACTIVATED CHARCOAL AS ADSORBENT TO IMPROVE THE QUALITY OF WASTE COOKING OIL”. Chemistry Notes, Vol. 2, no. 2, Dec. 2020, pp. 11-20, doi:10.35508/cn.v2i2.3268.