(left to right): Charles Robert Darwin (1809-1882) and Emily Catherine Darwin (1810-1866)

Chicago citation style
(left to right): Charles Robert Darwin (1809-1882) and Emily Catherine Darwin (1810-1866). Retrieved from the Digital Public Library of America, http://collections.si.edu/search/results.htm?q=record_ID%3Asiris_arc_296676&repo=DPLA. (Accessed November 18, 2018.)
APA citation style
(left to right): Charles Robert Darwin (1809-1882) and Emily Catherine Darwin (1810-1866). Retrieved from the Digital Public Library of America, http://collections.si.edu/search/results.htm?q=record_ID%3Asiris_arc_296676&repo=DPLA
MLA citation style
Retrieved from the Digital Public Library of America <http://collections.si.edu/search/results.htm?q=record_ID%3Asiris_arc_296676&repo=DPLA>.
Note: These citations are programmatically generated and may be incomplete.