R. B. Simon, Carl W. Stover, D. G. Howell, Garnett P. Williams, Geological Survey (U.S.), J. H. Minsch, Linda Graves Marcus, Robert Morrison Hamilton, Sam M. Pickering, David S. McCulloch, Michael W. Higgins, B. Glen Reagor, John Graham Vedder, W. J. Person · 1949
No author available
· 1980