Akpan, Etorobong Godwin. “The Axiomatic Method and Model Theory in Mathematics and Logic: An Expository Analysis”. American Journal of Social and Humanitarian Research 3, no. 12 (December 31, 2022): 283–290. Accessed May 16, 2024. https://globalresearchnetwork.us/index.php/ajshr/article/view/1847.