Шаповалов, Ю. І., Мандзій, Б. А., & Бачик, Д. Р. (2015). About the accuracy of assessment of stability of linear periodically time-variable circuits by the frequency symbolic method. Visnyk NTUU KPI Seriia - Radiotekhnika Radioaparatobuduvannia, (61), 13-22. https://doi.org/10.20535/RADAP.2015.61.13-22