Joseph, O. Akindele Adekugbe. “Evolutionary Sequence of Spacetime and Intrinsic Spacetime and Associated Sequence of Geometries in Metric Force Fields I”. Physical Science International Journal 25, no. 10 (December 14, 2021): 1-20. Accessed January 26, 2022. https://journalpsij.com/index.php/PSIJ/article/view/30284.