Kamaruddin, S. B. A., N. A. M. Ghanib, C.-Y. Liong, and A. A. Jemain. “Firearm Classification Using Neural Networks on Ring of Firing Pin Impression Images”. ADCAIJ: Advances in Distributed Computing and Artificial Intelligence Journal, vol. 1, no. 3, July 2013, pp. 27-34, doi:10.14201/ADCAIJ20121312734.