Widyasti, Arum Restu, et al. “THE DEVELOPMENT OF STANDARDIZATION NATURAL COLOUR FROM BATIK OF STEAM BARK (Caesalpinia Sappan L) BY SPECTROSCOPHY METHOD”. Jurnal Penelitian Saintek, vol. 22, no. 1, Aug. 2017, pp. 49-58, doi:10.21831/jps.v22i1.14850.