Gerta Keller, Thierry Adatte, Wolfgang Stinnesbeck, Mario Rebolledo-Vieyra, Jaime Urrutia Fucugauchi, Utz Kramar, and Doris Stüben: Chicxulub impact predates the K-T boundary mass extinction (PMC374316) PNAS. 16.3.2004. The National Academy of Sciences. Arkistoitu 1.8.2013. (englanniksi)
Gerta Keller, Thierry Adatte, Wolfgang Stinnesbeck, Mario Rebolledo-Vieyra, Jaime Urrutia Fucugauchi, Utz Kramar, and Doris Stüben: Chicxulub impact predates the K-T boundary mass extinction (PMC374316) PNAS. 16.3.2004. The National Academy of Sciences. Arkistoitu 1.8.2013. (englanniksi)