Labor productivity in Illinois underground coal mining
By: by J. Edward Ely.
Published: 1940
Language: eng
Format: Microform
Number of pages: 344
Subjects: Coal mines and mining -- Labor productivity -- Illinois.
Notes: Thesis--Yale University, 1940.

Microfilm. New Haven : Yale University Library, Publications Office, 1975. 1 microfilm reel ; 35 mm.