T. M. Hamdy, M. Galal, A. G. Ismail, and R. M. Abdelraouf, “Evaluation of Flexibility, Microstructure and Elemental Analysis of Some Contemporary Nickel-Titanium Rotary Instruments”, Open Access Maced J Med Sci, vol. 7, no. 21, pp. 3647–3654, Oct. 2019.