Bailey, S. W. and Cameron, E. N., 1951. Temperature of mineral formation in bottom run lead-zinc deposits of the Upper Mississippi Valley, as indicated by liquid inclusions. Economic Geology, v. 46, p. 626-649.
Bain, H. F., 1905, Zing and lead deposits of northwestern Illinois: U. S. Geol. Survey Bull. 246, 56 p.
Bain, H. F., 1906, Zinc and lead deposits of the upper Mississippi Valley: U. S. Geol. Survey Bull. 294, 155 p.
Bain, H. F., 1907. Zinc and lead deposits of the Upper Mississippi Valley. Wisconsin Geological and Natural History Survey, Bulletin 19, Economic Series No. 12, p. 1-148.
Bradbury, J. C., 1955. Geochemical prospecting in the zinc-lead district of Northwestern Illinois. Illinois Geological Survey Report of Investigations 179, p. 1-11.
Brown, C. E., Collins, L. G. and Crosby, P., 1955, Geology and zinc-lead deposits in the Couler Valley area, Dubuque County, Iowa: U. S. Geol. Survey Mineral Investigations Field Studies Map MF 42.
Brown, C. E. and Whitlow, J. W., 1960. Geology of the Dubuque South Quadrangle, Iowa-Illinois. U. S. Geological Survey Bulletin 1123A, 93 p.
Brown, C. E., Whitlow, J. W. and Crosby, P., 1957, Geology and zinc-lead deposits in the Catfish Creek area, Dubuque County, Iowa: U. S. Geol. Survey Mineral Investigations Field Studies Map MF 116.
Calvin, S. and Bain, H. F., 1900, Geology of Dubuque County: Iowa Geol. Survey Ann. Report. v. 10, p. 379-622.
Cannon, R. S. and Pierce, A. P. 1969. Lead isotope guides for Mississippi Valley lead-zinc exploration. U. S. Geological Survey Bulletin 1312G, p. 1-20.
Dockal, J. A., 1973, Bedrock Geochemical Sampling Near Lead-zinc Mineralizations, Dubuque, Iowa. Unpublished thesis, Iowa State University, 178 p.
Dockal, J. A., 1974, Geology of the crevice caves of Dubuque, Iowa (abstract): Program of the 1974 National Speleological Society Annual Convention at Decorah, Iowa; p. 8.
Dockal, J. A., 1977, Development of the lead-zinc mineralized crevices of Dubuque, Iowa (abstract): Abstract of Papers, Iowa Academy of Sciences Annual Meeting, 1977, p. 43.
Dockal, J. A., 1978, Geologic hazards related to lead-zinc mining at Dubuque, Iowa (abstract): Abstracts of Papers, Iowa Academy of Sciences Annual Meeting, 1978, p. 49.
Dockal, J. A., 1982, Memorial needed to mining heritage: Telegraph Herald, Dubuque, Iowa, February 11, 1982, p. 4.
Flint, A. E. and Brown, C. E., 1954, Geology and zinc-lead deposits in the Durango area, Dubuque County, Iowa: U. S. Geol. Survey Mineral Investigations Field Studies Map MF 33.
Flint, A. E. and Brown, C. E., 1956, Exploratory drilling of geologic structures for evidences of zinc or lead ore in Dubuque County, Iowa: U. S. Geol. Survey Bull. 1027-K, p. 471-499.
Heyl, A. V., Jr., Agnew, A. F., Behre, C. H., Jr., Lyons, E. J., and Hershey, H. G., 1945, Geologic map of the Center Grove-Pikes Peak area, Dubuque County, Iowa: U. S. Geol. Survey Strategic Min. Inv. Prelim. Map 3-203.
Heyl, A. V., Jr., Agnew, A. F., Lyons, E. J., and Behre, C. H., Jr., 1959, The geology of the upper Mississippi Valley Zinc-Lead District: U. S. Geol. Survey Professional Paper 309, 310 p.
Leonard, A. G., 1893a. Occurrence of zinc in northeastern Iowa. Iowa Academy of Science, vol. 1, part 4, p. 48-52.
Leonard, A. G., 1893b. Satin Spar from Dubuque. Iowa Academy of Science, vol. 1, part 4., p. 52-55.
Leonard, A. G., 1895. Recent developments in the Dubuque lead and zinc mines. Iowa Academy of Science, vol. 3, p. 64-66.
Leonard, A. G., 1897, Lead and zinc deposits of Iowa: Iowa Geol. Survey Ann. Rept., v. 6, p. 9-66.
Lincoln, F. C., 1948, Dubuque lead-zinc district, Iowa: U. S. Bur. Mines Rept. Inv. 4212, 7 p.
Ludvigson, G. and Dockal, J. A., 1984, The geology and history of lead mining in Dubuque: Iowa Geology, Iowa Geological Survey, no. 9, p. 4-9.
Whitney, J. D., 1858, p. 422-468, in Hall, James, and Whitney, J. D., Report on the geological survey of the State of Iowa (1855-1856). v/ 1. Geology, 472 p.
Many of these publications are obscure and difficult to find. Searching the electronic catalogs of the following academic libraries should help you find most. In the future I will be posting here some of these as PDF files.
e-Library of Iowa State University, Ames, Iowa
University of Iowa, Iowa City, Iowa Libraries
Loras College of Dubuque, Iowa Wahlert Memorial Library