Ward, P. D. (1992). On Methuselah's trail: Living fossils and the great extinctions. W.H. Freeman.
Cita Chicago Style (17a ed.)Ward, Peter Douglas. On Methuselah's Trail: Living Fossils and the Great Extinctions. New York: W.H. Freeman, 1992.
Cita MLA (9a ed.)Ward, Peter Douglas. On Methuselah's Trail: Living Fossils and the Great Extinctions. W.H. Freeman, 1992.
Precaución: Estas citas no son 100% exactas.