500, 401. The Country of the 'Blackfeet' Indians.
MLA
McClintock, Walter, 1870-1949. 500, 401. The Country of the 'Blackfeet' Indians.. Box 63, folder 3222. 1947. https://collections.library.yale.edu/catalog/2008786.
APA, 6th edition
McClintock, Walter, 1870-1949. (["Box 63, folder 3222"])(1947)[500, 401. The Country of the 'Blackfeet' Indians.]. https://collections.library.yale.edu/catalog/2008786.