Mural Study #4:

Chicago citation style
John Decker, 1895 - 1947. Mural Study #4. c. 1941. Retrieved from the Digital Public Library of America, http://collections.si.edu/search/results.htm?q=record_ID%3Anpg_NPG.93.376&repo=DPLA. (Accessed December 19, 2018.)
APA citation style
John Decker, 1895 - 1947, (c. 1941) Mural Study #4. Retrieved from the Digital Public Library of America, http://collections.si.edu/search/results.htm?q=record_ID%3Anpg_NPG.93.376&repo=DPLA
MLA citation style
John Decker, 1895 - 1947. Retrieved from the Digital Public Library of America <http://collections.si.edu/search/results.htm?q=record_ID%3Anpg_NPG.93.376&repo=DPLA>.
Note: These citations are programmatically generated and may be incomplete.