Haghani, J., Raoof, M. and Pourahmadi, S. (2008) “Ex-Vivo Evaluation of X-Ray Horizontal Angle for Separating the Canals of Four-Canal First Mandibular Molars”, Iranian Endodontic Journal, 3(1), pp. 143–146. doi: 10.22037/iej.v2i4.292.