Bird, Francis A.
Robert F. Dame, Inc. , 1981
Buku Teks
Vickery, Bertram George
Donnington Press, 1971
Buku Teks
Atrill, Peter
Prentice-Hall, 1996
Buku Teks
Wise, A. C.
Longman, 1970
Buku Teks
Williams, Jan R.
Harcourt brace jovannovich, Publishers , 1989
Buku Teks