Snelgrove, D. A. K. (1960). Opportunities in geology and geological engineering. Vocational Guidance Manuals.
Chicago-referens (17:e uppl.)Snelgrove, Dr. Alfred Kitchener. Opportunities in Geology and Geological Engineering. New York: Vocational Guidance Manuals, 1960.
MLA-referens (9:e uppl.)Snelgrove, Dr. Alfred Kitchener. Opportunities in Geology and Geological Engineering. Vocational Guidance Manuals, 1960.
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