Taxonomy, biostratigraphy, and phylogeny of Eocene Globigerina, Globoturborotalita, Subbotina, and TurborotalitaCushman Foundation Special Publication 41: Allen Press111–168
Olsson, R. K., Hemleben, C., Huber, Brian T., and Berggren, William A. 2006. "Taxonomy, biostratigraphy, and phylogeny of Eocene Globigerina, Globoturborotalita, Subbotina, and Turborotalita." In Atlas of Eocene Planktonic Foraminifera. Pearson, Paul N., Olsson, R. K., Hemleben, C., Huber, Brian T., and Berggren, William A., editors. 111–168. Cushman Foundation Special Publication 41: Allen Press.