MLA

of Strategic Services. Research, United States. Office, and Analysis Branch. Camarines Sur. Western Part. 1945. https://collections.library.yale.edu/catalog/15238631.

APA, 6th edition

of Strategic Services. Research, U. S. O., & Branch, A. (1945). Camarines Sur. Western part. [Maps]. https://collections.library.yale.edu/catalog/15238631.