Andasuryani, Andasuryani, et al. “Determination of Catechin Content in Gambir Powder from Dried Gambir Leaves Quickly Using FT NIR PLS Model”. International Journal on Advanced Science, Engineering and Information Technology, vol. 4, no. 5, Oct. 2014, pp. 303-7, doi:10.18517/ijaseit.4.5.423.