Lourens, L. J.; Antonarakou, A.; Hilgen, F. J.; Van Hoof, A. A. M.; Vergnaud-Grazzini, C.; Zachariasse, W. J. (1996): Evaluation of the Plio-Pleistocene astronomical timescale. American Geophysical Union, Washington, DC, United States, Paleoceanography, 11 (4), 391-413, georefid:2001-035476