Ellis, Robert
Harcourt Brace Javanovich, 1978
Buku Teks
Boddy, Michael
Currency Press, 1974
Buku Teks
London Collier-Macmillan 1965,
Buku Teks
Suenobu, Mineo
Kobe University of Commerce, 1999
Buku Teks
Fred Genesee, Kathryn Lindholm-Leary, William M. Saunders, Donna Christian
Cambridge University Press, 2008
Buku Teks