Carbonizing properties and petrographic composition of thick Freeport-bed coal from Harmar mine, Harmarville, Allegheny County, Pa. : and the effect of blending this coal with Pocahontas No. 3- and 4-bed coals / by J.D. Davis, D.A. Reynolds, G.C. Sprunk, C.R. Holmes, and J.T. McCartney (1943)