Олійник, О. Ю., and Ю. К. Тараненко. “THE STRINGS FREE OSCILLATIONS EQUATION NUMERICAL SOLUTION TAKING TO ACCOUNT THE STRING BENDING LINE INITIAL CONFIGURATION”. METHODS AND DEVICES OF QUALITY CONTROL, no. 2(39), Oct. 2017, pp. 97-101, https://mpky.nung.edu.ua/index.php/mpky/article/view/414.