M. Agung Nugroho, M. Mediatrix Sebatubun, and S. ., “Identifying Arabica Raw Coffee Bean Varieties through Feature Extraction GLCM and Circularity”, IJET, vol. 7, no. 4.44, pp. 117–121, Dec. 2018, doi: 10.14419/ijet.v7i4.44.26964.