F. Ari Mukti, C. Eswaran, N. Hashim, H. Chiung Ching, and M. Uvaze Ahamed Ayoobkhan, “An automated grading system for diabetic retinopathy using curvelet transform and hierarchical classification”, IJET, vol. 7, no. 2.15, pp. 154–157, Apr. 2018, doi: 10.14419/ijet.v7i2.15.11375.