Description
| Item Description: | At head of title: United States. Department of the Interior. Ray Lyman Wilbur, secretary. Office of education. William John Cooper, commissioner.
Published also as thesis (PH.D) University of Pennsylvania. |
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| Physical Description: | v, 160 p. incl. tables, diagrs, forms. 23 cm. |
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| Bibliography: | Bibliography: p. 153-155.
Bibliographical footnotes. |
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