Parhi, N. and Chand, S. (1999) “Oscillation of Second Order Neutral Delay Differential Equations With Positive and Negative Coefficients”, The Journal of the Indian Mathematical Society, 66(1-4), pp. 227–235. Available at: https://informaticsjournals.co.in/index.php/jims/article/view/22006 (Accessed: 7 November 2024).