por Ohio. State Commissioner of Common Schools.
por Armco Culvert Manufactures Association (Ohio).
por Jeffrey Manufacturing Company (Columbus, Ohio).
por Orton, Edward, 1863-1932 [autor] | Peppel, Samuel Vernon [autor] | Geological Survey Ohio.
por Lord, Nathaniel Wright, 1854-1911 [autor] | Ohio State University. Metallurgical Laboratory.