Shchigolev, V.K. “Variational Iteration Method for Studying Perihelion Precession and Deflection of Light in General Relativity”. International Journal of Physical Research 4, no. 2 (August 27, 2016): 52–57. Accessed May 4, 2024. https://www.sciencepubco.com/index.php/IJPR/article/view/6530.