TRIPATHY, Arun Kumar, and Shyam Sundar SANTRA. “On Oscillatory Second Order Nonlinear Impulsive Systems of Neutral Type”. Studia Universitatis Babeș-Bolyai Mathematica, vol. 65, no. 4, Nov. 2020, pp. 503–519, doi:10.24193/subbmath.2020.4.03.