Tortoriello, Thomas R.
MaGraw-Hill , 1978
Buku Teks
Lacy, Stephen
Lawrence Erlbanan Associates, 1993
Buku Teks
Teare, Richard, author
Cassell, 1996
Buku Teks
Smith, H.W., author
Prentice-Hall, 1981
Buku Teks
Hammersley, Martyn, author
Routledge, 1992
Buku Teks