MLA

Lachaise, Gaston, 1882-1935. [Correspondence with Isabel Lachaise]. Letters to Isabel Lachaise [1921-1928]. [1928] October 30. https://collections.library.yale.edu/catalog/2041670.

APA, 6th edition

Lachaise, Gaston, 1882-1935. (["Letters to Isabel Lachaise [1921-1928]"])([1928] October 30)[[Correspondence with Isabel Lachaise]]. https://collections.library.yale.edu/catalog/2041670.