Rosa, Frank, author
McGraw-Hill, 1985
Buku Referensi
Willis, Claire, author
Pitman, 1992
Buku Teks
Brown, T. Merritt, author
Macmillan, 1970
Buku Teks
Global Electronic Records Association, 2003
Buku Referensi
Sheppard, Deri, author
McGraw-Hill, 1995
Buku Teks