A. B. Hoen, Discussion of the Requisite Qualities of Lithographic Limestone, with Report on Tests of the Lithographic Stone of Mitchell County, Iowa, Iowa Geological Survey Annual Report, 1902, Des Moines, 1903; pages 339–352.
britannica.com
Peterdi, Gabor F. (2021): "Lithography" section of "Printmaking" article. Encyclopedia Britannica online. Accessed 23 November 2021.