Sources in this list include books, newspapers, and periodicals. Book citations are listed by author's last name and date of publication (i.e., Angel 1881), while books about Mark Twain take a separate abbreviation (i.e., MTB). Newspapers are listed by place and title. Periodicals are given by title only (i.e., The Californian). The list is in alphabetical order.
"Section" here refers to the places and periods in which Mark Twain wrote his tales and sketches. The editors of the Early Tales & Sketches divided volumes 1 and 2 into sections based on these places and periods.
"Series" here refers to the thematic groupings editors of the Early Tales & Sketches gave to writings that either treated the same subject matter (i.e., "Two Descents into the Spanish Mine") or were in fact a series (i.e., "Answers to Correspondents").