MLA

Simpson, Randolph Linsly, 1927-1992. Studio unknown Group portrait, taken in field; six white soldiers in front of and within tent, black boy wearing kepi seated. Carte de visite. Box 11, folder 359. circa 1861. https://collections.library.yale.edu/catalog/2003872.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 11, folder 359"])(circa 1861)[Studio unknown Group portrait, taken in field; six white soldiers in front of and within tent, black boy wearing kepi seated. Carte de visite]. https://collections.library.yale.edu/catalog/2003872.