Felix , I. C., O. O. Famoofo, and S. M. Akintewe. “A New Symmetric P-Stable Obrechkoff Method With Optimal Phase Lag for Oscillatory Problems ”. Earthline Journal of Mathematical Sciences, Vol. 1, no. 1, Jan. 2019, pp. 105-18, doi:10.34198/ejms.1119.105118.