Avian paleontology at the close of the 20th century : proceedings of the 4th international meeting of the Society of avian palentology and evolution, Washington, D.C., 4-7 June 1996 - Olson, Storrs L., 1944-; Wellnhofer, Peter, 1936-; Mourer-Chauviré, Cécile; Steadman, David W., 1951-; Martin, Larry D. (Smithsonian contributions to paleobiology, 1999)