Carbonizing Properties of Butler County, Pa., Coals by Mark I. Copeland, John Ward Smith, Donald W. Frommer, David E. Wolfson, George W. Birge, Raynard V. Lundquist, Lloyd Harold Banning, Gerald V. Gibbs, Arthur F. Colombo, Eben L. Singleton, C. A. Stone, Karl Clyde Dean, Francis Harold Gibson, William Harlan Ode, Vernal E. Edlund, R. S. Lang, Thomas T. Campbell, Joe B. Rosenbaum, A. A. Berk, A. C. Rice, C. S. Tout, Carl J. Chindgren, Donald William Scott, G. W. Elger, Gene Asai, Wesley T. Holmes, Ralph V. Higgins, G. L. Hopps, Irving L. Turner, Ivan L. Nichols, J. P. McCullough, L. Carpenter, Lester C. Bauerle, W. Floyd Holbrook, Alan J. Leighton, F. Donald Bloss