Twain, M., Anderson, F., Gibson, W. M., Howells, W. D., & Smith, H. N. (1967). Selected Mark Twain-Howells letters, 1872-1910. The Belknap Press of Harvard University Press.
Lua i Stíl Chicago (17ú heag.)Twain, Mark, Frederick Anderson, William M. Gibson, William Dean Howells, agus Henry Nash Smith. Selected Mark Twain-Howells Letters, 1872-1910. Cambridge, Massachusetts: The Belknap Press of Harvard University Press, 1967.
Lua MLA (9ú heag.)Twain, Mark, et al. Selected Mark Twain-Howells Letters, 1872-1910. The Belknap Press of Harvard University Press, 1967.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.