B. K. Jasem, “Correction of Spherical Aberration of an Immersion Lens Operating Under Space Charge Effect Described by a 2nd Order Equation”, IJP, vol. 8, no. 12, pp. 80–85, Nov. 2010, Accessed: Dec. 23, 2024. [Online]. Available: https://ijp.uobaghdad.edu.iq/index.php/physics/article/view/854