Berggren, W. A.; Poore, R. Z. (1975): Late Miocene - early Pliocene planktonic foraminiferal biochronology; Globorotalia tumida and Sphaeroidinella dehiscens lineages. Woods Hole Oceanographic Institution, Woods Hole, MA, United States, Collected Reprints - Woods Hole Oceanographic Institution, 1974, Part 3, georefid:1977-004923