Sahni A, Kapoor R, Gandhi K, Kumar D, Datta G, Malhotra R.
A Comparative Evaluation of Efficacy of Electronic Apex Locator, Digital Radiography, and Conventional Radiographic Method for Root Canal Working Length Determination in Primary Teeth: An In Vitro Study. 
Int J Clin Pediatr Dent
2020;
13
(5):523-528.