MLA

Twain, Mark, 1835-1910. Who was Sarah Findlay? By Mark Twain. With a suggested solution of the mystery by J.M. Barrie.. April, 1917.. https://collections.library.yale.edu/catalog/15535961.

APA, 6th edition

Twain, Mark, 1835-1910. (April, 1917.)[Who was Sarah Findlay? By Mark Twain. With a suggested solution of the mystery by J.M. Barrie.]. https://collections.library.yale.edu/catalog/15535961.