Chenarani, Atefeh, Shafiee Ardestani, Meysam, Vahidinia, Mohammad. Biocorrelation, Biostratigraphy and determination basal of the Aptian stage at Tirgan Formation , west of Kopeh-Dagh sedimentary basin, NE Iran. Iranian Journal of  Petroleum Geology. 2022;11(21):78-97. 10.52547/ispg.33928.11.21.78