Pred, Allan R.
The Royal University of Lund, 1973
Buku Teks
Pred, Allan
Routledge, 1995
Buku Teks
Gelinas, Ulric J., author
PWS-KENT Publishing Company, 1990
Buku Teks
Beals, Alan R
Holt, Rinehart and Winston, 1967
Buku Teks
O`Brien, James A., 1936-, author
McGraw-Hill, 2003
Buku Teks