MLA

Oastler, Frank Richard, 1871-1936. Redwoods, Grand Canyon, Zion National Park, Bryce National Park, Sequoia, Yosemite, Lassen. Box 50, folder 50. [1928]. https://collections.library.yale.edu/catalog/15829931.

APA, 6th edition

Oastler, Frank Richard, 1871-1936. (["Box 50, folder 50"])([1928])[Redwoods, Grand Canyon, Zion National Park, Bryce National Park, Sequoia, Yosemite, Lassen]. https://collections.library.yale.edu/catalog/15829931.