The friend that have it I do wrong ...
MLA
Yeats, W. B. (William Butler), 1865-1939. The friend that have it I do wrong .... Undated. https://collections.library.yale.edu/catalog/9998732.
APA, 6th edition
Yeats, W. B. (William Butler), 1865-1939. (Undated)[The friend that have it I do wrong ...]. https://collections.library.yale.edu/catalog/9998732.