Dr. Mohammed Thamer Alqahtani, Dr. Saad Ali Sabrah, and Dr. Mohammed Aied Aljafel, “PREVALENCE OF MAXILLARY SECOND PREMOLAR TEETH WITH 2 CANALS IN SAUDI POPULATION OF EASTERN AND SOUTHERN REGIONS”, Med. res. chronicles, vol. 4, no. 05, pp. 560-562, Oct. 2017.