Willie Lincoln (left) and Tad Lincoln (right)

Chicago citation style
Willie Lincoln (left) and Tad Lincoln (right). ca. 1859. Retrieved from the Digital Public Library of America, http://contentdm.acpl.lib.in.us/cdm/ref/collection/p15155coll1/id/265. (Accessed June 23, 2018.)
APA citation style
(ca. 1859) Willie Lincoln (left) and Tad Lincoln (right). Retrieved from the Digital Public Library of America, http://contentdm.acpl.lib.in.us/cdm/ref/collection/p15155coll1/id/265
MLA citation style
Retrieved from the Digital Public Library of America <http://contentdm.acpl.lib.in.us/cdm/ref/collection/p15155coll1/id/265>.
Note: These citations are programmatically generated and may be incomplete.