Proceedings of the National Academy of Sciences of the United States of America. 9/30/2003, Vol. 100 Issue 20, p11517-11522. 6p. 2 Color Photographs, 3 Diagrams, 1 Chart, 9 Graphs.
Proceedings of the National Academy of Sciences of the United States of America. 5/13/2003, Vol. 100 Issue 10, p5956. 6p. 24 Black and White Photographs, 6 Diagrams, 2 Charts.
Proceedings of the National Academy of Sciences of the United States of America. 2/18/2003, Vol. 100 Issue 4, p1592. 6p. 6 Black and White Photographs, 2 Charts, 32 Graphs.
Proceedings of the National Academy of Sciences of the United States of America. 5/14/2002, Vol. 99 Issue 10, p6955. 6p. 12 Color Photographs, 3 Black and White Photographs, 1 Diagram, 1 Chart, 4 Graphs.