MLA

Pound, Ezra, 1885-1972. Blast, Poems from: typescript. Box 111, folder 4678. n.d.. https://collections.library.yale.edu/catalog/10460168.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 111, folder 4678"])(n.d.)[Blast, Poems from: typescript]. https://collections.library.yale.edu/catalog/10460168.