Biostratigraphical investigation of middle-early Miocene sediments from a section of AK-1 well, onshore Niger Delta: Insights from calcareous nanofossils. Fountain Journal of Natural and Applied Sciences [Internet]. 2023 Jun. 30 [cited 2026 Apr. 2];12(1). Available from: http://www.fountainjournals.com/index.php/FUJNAS/article/view/439