Boel, T. ., Kartika, D. ., & Liliana, L. (2017). Root Canal Configuration Of Permanent Mandibular First Molars Using Radiographic Tube Shift Technique On Dentistry Student Of University Of Sumatera Utara. IIUM Medical Journal Malaysia, 16(2). https://doi.org/10.31436/imjm.v16i2.1098