MLA

Polovtsoff, Alexandre, 1867-. Petr Veliki? [Peter the Great] p.257-272, "L'oeuvre de Pierre le Grand..." [On Elizabeth, empress of Russia] (notebook). Box 1, folder 1c. 1918-1934. https://collections.library.yale.edu/catalog/32206123.

APA, 6th edition

Polovtsoff, Alexandre, 1867-. (["Box 1, folder 1c"])(1918-1934)[Petr Veliki? [Peter the Great] p.257-272, "L'oeuvre de Pierre le Grand..." [On Elizabeth, empress of Russia] (notebook)]. https://collections.library.yale.edu/catalog/32206123.