Archival & Special Collections. (n.d.). Timeline: Sleeman Family History and Events. Retrieved November 17, 2016, from http://www.lib.uoguelph.ca/find/find-type-resource/archival-special-collections/sleeman-collection/timeline
City of Toronto. (2014). HERITAGE PROPERTY RESEARCH AND EVALUATION REPORT R. G. MCLEAN BUILDING AND BARCLAY, CLARK AND COMPANY BUILDING 26 LOMBARD STREET, TORONTO. Retrieved November 17, 2016, from http://www.toronto.ca/legdocs/mmis/2015/te/bgrd/backgroundfile-75723.pdf
Guelph Public Library. (2013). Sleeman, George. Retrieved November 10, 2016, from https://www.guelphpl.ca/archives/famous_person.cfm?id=27
Ol' duffer. (2013). University of Guelph to Preserve Sleeman Family History. Retrieved November 17, 2016, from http://familylineagesandhistory.blogspot.ca/2013_03_01_archive.html
Parrott-Sheffer, C. (2008, June 6). Lithography. Retrieved November 19, 2016, from https://www.britannica.com/topic/lithography