Меловой период

Georgescu M.D. (2017) Upper Cretaceous planktic foraminiferal biostratigraphy // Studia UBB Geologia, Vol. 61. no.1-2, P.5 – 20. DOI: https://doi.org/10.5038/1937-8602.61.1.1297
http://scholarcommons.usf.edu/cgi/viewc ... t=geologia