A. M. A. El-Sayed, Zaki. F. A. EL-Raheem and N. A. O. Buhalima 2018. Eigenfunction expansion of the Sturm-Liouville equation with a non-local boundary condition. Malaya Journal of Matematik. 6, 02 (Apr. 2018), 338–343. DOI:https://doi.org/10.26637/MJM0602/0006.