Changes in technology and labor requirements in the crushed-stone industry

Kantor, Harry S.
Philadelphia, Pa. : Works progress administration, National research project, in cooperation with Department of the interior, Bureau of mines, 1939.

Rock drilling

Nighman, C. E.
Philadelphia, Pa., [publisher not identified], 1940.

Technology, employment, and output per man in copper mining

Leong, Yau Sing, 1899-
Philadelphia, Pa., [publisher not identified], 1940.

Technology, employment, and output per man in iron mining

Yaworski, Nicholas.
Philadelphia, Pa., [publisher not identified], 1940.

Technology, employment, and output per man in petroleum and natural-gas production

Kiessling, O. E. (Oscar Edward), 1901-1993.
Philadelphia, Pa., [publisher not identified], 1939.

Technology, employment, and output per man in phosphate-rock mining, 1880-1937

Haskell, A. Porter.
Philadelphia, Pa. : Works progress administration, National research project, in cooperation with Department of the interior, Bureau of mines, 1938.