Cite

Autograph letter, signed, to Henry Ferguson, Hartford (Conn.)

MLA

Clemens, Samuel Langhorne, 1835-1910, Twain, Mark, 1835-1910. Autograph letter, signed, to Henry Ferguson, Hartford (Conn.). Folder 3. 1899 December 21. https://collections.library.yale.edu/catalog/2047269.

APA, 6th edition

Clemens, Samuel Langhorne, 1835-1910, & Twain, Mark, 1835-1910. (["Folder 3"])(1899 December 21)[Autograph letter, signed, to Henry Ferguson, Hartford (Conn.)]. https://collections.library.yale.edu/catalog/2047269.