Pennsylvania. Bureau of Topographic and Geologic Survey, United States. Bureau of Mines, Ashley, G. H., Sisler, J. D., & Reese, J. F. (1925). Bituminous coal fields of Pennsylvania. [publisher not identified].
Chicago Style (17th ed.) CitationPennsylvania. Bureau of Topographic and Geologic Survey, United States. Bureau of Mines, Geo. H. Ashley, James D. Sisler, and John F. Reese. Bituminous Coal Fields of Pennsylvania. Harrisburg: [publisher not identified], 1925.
MLA (9th ed.) CitationPennsylvania. Bureau of Topographic and Geologic Survey, et al. Bituminous Coal Fields of Pennsylvania. [publisher not identified], 1925.
Warning: These citations may not always be 100% accurate.