MLA

Clemens, Samuel Langhorne, 1835-1910. Scrapbook containing newspaper clippings of contributions by Mark Twain to the Californian and the Territorial Enterprise. Box 13. undated. https://collections.library.yale.edu/catalog/15825540.

APA, 6th edition

Clemens, Samuel Langhorne, 1835-1910. (["Box 13"])(undated)[Scrapbook containing newspaper clippings of contributions by Mark Twain to the Californian and the Territorial Enterprise]. https://collections.library.yale.edu/catalog/15825540.