Mohamed, Ibrahim S., Hamid M. Khttab, Said K. Elsayed, Mohsen G. El-Noby, and Shady G. Elrammah. 2022. “A New Progressive and Efficient Royalty Model for Upstream Petroleum Industry”. International Journal of Energy Economics and Policy 12 (3):287-97. https://doi.org/10.32479/ijeep.13153.