“About the Accuracy of Assessment of Stability of Linear Periodically Time-Variable Circuits by the Frequency Symbolic Method”. 2015. Visnyk NTUU KPI Seriia - Radiotekhnika Radioaparatobuduvannia, no. 61 (June): 13-22. https://doi.org/10.20535/RADAP.2015.61.13-22.