N. L. T. Thenu, I. M. Ariana, A. Zubaydi, and D. Arifianto, “Observation of Changes in Acoustic Emission and Vibration Signals to Transverse Crack on Rotating Shaft: An Experiment Investigation”, Int. J. Adv. Sci. Eng. Inf. Technol., vol. 7, no. 5, pp. 1853–1860, Oct. 2017.