Olson, Storrs L. Presbyornis and the origin of the Anseriformes (Aves Charadriomorphae) Storrs L. Olson and Alan Feduccia - Washington Smithsonian Institution Press 1980 - 24p. ill. 26cm. - Smithsonian contributions to zoology no.323 . LCCN: 80-607065 Subjects--Topical Terms: Anseriformes--EvolutionPresbyornis--EvolutionBirds--Evolution