Wyderka, Zdzisław. “About Monotonic and Oscillatory Solutions of Scalar Linear Differential Equations With Measures As Coefficients”. Annales Mathematicae Silesianae 5 (September 30, 1991): 68-74. Accessed May 16, 2024. https://journals.us.edu.pl/index.php/AMSIL/article/view/14283.