Lesley, J. P. (1874). A collection of occasional surveys of iron, coal and oil districts in the United States: Made during the last ten years. McCalla & Stavely.
Chicago-referens (17:e uppl.)Lesley, J. P. A Collection of Occasional Surveys of Iron, Coal and Oil Districts in the United States: Made During the Last Ten Years. Philadelphia: McCalla & Stavely, 1874.
MLA-referens (8:e uppl.)Lesley, J. P. A Collection of Occasional Surveys of Iron, Coal and Oil Districts in the United States: Made During the Last Ten Years. McCalla & Stavely, 1874.
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