Wright, Quincy
Appleton-Century-Crofts, 1955
Buku Teks
Mathisen, Trygve
Oslo University Press, 1959
Buku Teks
Griffith, Martin
Routledge, 2002
Buku Teks
edited by Beth A. Simmons and Richard H. Steinberg
Cambridge University Press, 2006
Buku Teks
Numelin, Ragnar
Oxford University Press, 1950
Buku Teks