Earliest evolution associated with closure of the tropical American seawayv. 93No. 12National Academy of Sciences (U.S.)6069–6072
Collins, Laurel S., Budd, Ann F., and Coates, Anthony G. 1996. "Earliest evolution associated with closure of the tropical American seaway." Proceedings of the National Academy of Sciences of the United States of America, 93, (12) 6069–6072.