Drake, Charles D.
Sweet and Maxwell , 1972
Buku Teks
Riant Nugroho Dwidjowijoto, author
2011
Artikel Jurnal
Martin, Susan K., author
Knowledge Industry, 1986
Buku Teks
Jackson, Susan E., author
South Westh Western College, 2000
Buku Teks
Sheahan, John
University Press 1963, 1963
Buku Teks