Jenkins, O. P. (1924). Geological investigation of the coal fields of Skagit county, Washington. F.M. Lamborn, public printer.
Cita Chicago Style (17a ed.)Jenkins, Olaf P. Geological Investigation of the Coal Fields of Skagit County, Washington. Olympia: F.M. Lamborn, public printer, 1924.
Cita MLA (8a ed.)Jenkins, Olaf P. Geological Investigation of the Coal Fields of Skagit County, Washington. F.M. Lamborn, public printer, 1924.
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