MLA

Gibbs, J. Willard (Josiah Willard), 1839-1903. Michelson, Albert Abraham (1852-1931) - 6 autograph letters, signed, to [Josiah Willard] Gibbs. Cleveland.. Box 3, folder 95. 1884-1890. https://collections.library.yale.edu/catalog/2020779.

APA, 6th edition

Gibbs, J. Willard (Josiah Willard), 1839-1903. (["Box 3, folder 95"])(1884-1890)[Michelson, Albert Abraham (1852-1931) - 6 autograph letters, signed, to [Josiah Willard] Gibbs. Cleveland.]. https://collections.library.yale.edu/catalog/2020779.