Spectral analysis of the lower Eocene Wilkins Peak Member, Green River Formation, Wyoming: Support for Milankovitch cyclicity, Machlus, M. L.; Olsen, P. E.; Christie-Blick, N.; Hemming, S. R. , Earth and Planetary Science Letters, Apr 15, Volume 268, Issue 1-2, p.64-75, (2008), DOI 10.1016/j.epsl.2007.12.024 Abstract