Omar Ahmed Al-Badrani and Faris Nejris Hassan 2022. Calcareous nannofossils bioevent throughout the Cretaceous -Tertiary boundary in kh-4 well, Northern Iraq. Tikrit Journal of Pure Science. 26, 1 (Dec. 2022), 60–66. DOI:https://doi.org/10.25130/tjps.v26i1.100.