Steliga, I., J. Grydzhuk, and A. Dzhus. “An Experimental and Theoretical Method of Calculating the Damping Ratio of the Sucker Rod Column Oscillation”. Eastern-European Journal of Enterprise Technologies, vol. 2, no. 7(80), Apr. 2016, pp. 20-25, doi:10.15587/1729-4061.2016.66193.