Ballou, Ronald H.
Prentice Hall International I, 1992
Buku Teks
Statt, David A., author
Routledge, 1999
Buku Referensi
Hodgetts, Richard M., author
Harcourt College Publishers, 2001
Buku Teks
"Deep ,
Buku Teks
Batra G. S.
[publisher not identified], [date of publication not identified]
Buku Teks