MLA

Thomson, James Claude, 1889-. Metal box containing slides of China and Hong Kong; slide carousel #4 containing slides of Beijing (Peking), Great Wall of China, Summer Palace, Western Hills, etc.. 7, folder 157. circa 1949. https://collections.library.yale.edu/catalog/33376574.

APA, 6th edition

Thomson, James Claude, 1889-. (["7, folder 157"])(circa 1949)[Metal box containing slides of China and Hong Kong; slide carousel #4 containing slides of Beijing (Peking), Great Wall of China, Summer Palace, Western Hills, etc.]. https://collections.library.yale.edu/catalog/33376574.