Não informado. (1999). International Mining & Minerals. Institution of Mining Engineers.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. International Mining & Minerals. Doncaster, Inglaterra: Institution of Mining Engineers, 1999.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. International Mining & Minerals. Institution of Mining Engineers, 1999.
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