Steele, D. J. (1969). Modern developments in mining machinery. London: Virtue and Company.
Παραπομπή Chicago StyleSteele, D. J. Modern Developments in Mining Machinery. London: Virtue and Company, 1969.
Παραπομπή MLASteele, D. J. Modern Developments in Mining Machinery. London: Virtue and Company, 1969.
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