Spate, Oskar Hermann Kristian
Australia, New Zealand and the Pacific
Oxford University Press, 1965
 Buku Teks SO
Grant, Douglas
Mark Twain
Grove Press, 1962
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The Autobigraphy of Mark Twain
NY. Harper & Brothers
 Buku Teks
Mark Twain letters to mary
edited with a commerntary by Lewis G. Leary
Columbia University Press, 1961
 Buku Teks SO
Smith, Henry Nash
Mark Twain: the development of a writer
Belknap Press of Harvard University Press, 1967
 Buku Teks SO