“Review of an Accelerometer Based Digital Pen with Trajectory recognition Algorithm for Handwritten Digit and Gesture Recognition”, Int. J. Curr. Eng. Technol., vol. 4, no. 4, pp. 2396–2400, Aug. 2014, Accessed: Apr. 11, 2026. [Online]. Available: https://ijcet.evegenis.org/index.php/ijcet/article/view/1052