Columbia subject headings:
Paleontologists--Correspondence.
Simpson, George Gaylord, 1902-1984--Correspondence.
Vertebrates, Fossil.
Harvard subject headings:
Paleontologists--Correspondence.
Simpson, George Gaylord, 1902-1984--Correspondence.
Vertebrates, Fossil
Princeton subject headings:
Paleontologists--Correspondence.
Simpson, George Gaylord, 1902-1984--Correspondence.
Vertebrates, Fossil.