Baumgartner-Mora, Claudia, Peter O. Baumgartner, and Pascal Tschudin. “Late Oligocene Larger Foraminifera From Nosara (Nicoya Península, Costa Rica) and Indward (Carriacou, Lesser Antilles), Calibrated by 87sr/ 86sr Isotope Stratigraphy”. Revista geológica de América central 38 (March 24, 2007). Accessed December 20, 2024. https://revistas.ucr.ac.cr/index.php/geologica/article/view/4215.