Filippelli, G. M.; Ravelo, A. C. (1995): Sea level, phosphorites, and the phosphorus cycle. Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States, In: Hine, Albert C. (prefacer), Halley, Robert B. (prefacer), Linked Earth systems; congress program and abstracts; Vol. 1, 53, georefid:1997-039117