MLA

Williams, William Carlos, 1883-1963. "Thesis for Columbia College Literary Journal: A Few General Correctives to the Present State of American Poetry". Box 45, folder 1130-1131. undated. https://collections.library.yale.edu/catalog/17049591.

APA, 6th edition

Williams, William Carlos, 1883-1963. (["Box 45, folder 1130-1131"])(undated)["Thesis for Columbia College Literary Journal: A Few General Correctives to the Present State of American Poetry"]. https://collections.library.yale.edu/catalog/17049591.