World Register of Marine Species (WoRMS)
Stewartina ultimata Stevens & Stone, 2007
Hayward, B.W.; Le Coze, F.; Vachard, D.; Gross, O. (2026). World Foraminifera Database. Stewartina ultimata Stevens & Stone, 2007&nbsp;&#8224;. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1058907 on 2026-08-02
Stevens, C. H.; Stone, P. (2007). The Pennsylvanian–Early Permian Bird Spring Carbonate Shelf, Southeastern California: Fusulinid Biostratigraphy, Paleogeographic Evolution, and Tectonic Implications. Geological Society of America Special Paper. 429: 1-82.