Snelgrove, D. A. K. (1960). Opportunities in geology and geological engineering. Vocational Guidance Manuals.
Lua i Stíl Chicago (17ú heag.)Snelgrove, Dr. Alfred Kitchener. Opportunities in Geology and Geological Engineering. New York: Vocational Guidance Manuals, 1960.
Lua MLA (9ú heag.)Snelgrove, Dr. Alfred Kitchener. Opportunities in Geology and Geological Engineering. Vocational Guidance Manuals, 1960.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.