Clark, G. W. (2013). 19th century card photos: A step-by-step guide to identifying and dating cartes de visite and cabinet cards. Phototree.com.
Chicago Style (17th ed.) CitationClark, Gary W. 19th Century Card Photos: A Step-by-step Guide to Identifying and Dating Cartes De Visite and Cabinet Cards. [Wichita, Kansas]: Phototree.com, 2013.
MLA (9th ed.) CitationClark, Gary W. 19th Century Card Photos: A Step-by-step Guide to Identifying and Dating Cartes De Visite and Cabinet Cards. Phototree.com, 2013.
Warning: These citations may not always be 100% accurate.