Reschke, Cynthia, author
Te Neues, 2003
Buku Teks
Trulove, James Grayson, author
HarperCollins, 2001
Buku Referensi
Tyring, Stephen K., author
Elsevier, 2005, 2005
Buku Teks
PEMESA,
Majalah, Jurnal, Buletin
Coughlan, Robert, author
Time Incorporated, 1962
Buku Teks