Cram, Carol M., author
Cengage Learning , 2012
Buku Teks
Grauer, Robert T., author
Pearson Education, 2003
Buku Teks
Asikin, author
Elex Media Komputindo, 1990
Buku Teks
Muhamad Sean, author
2015
UI - Skripsi (Membership)
Goverment Information Office, 2002
Buku Referensi