Shah, Giriraj, author
Anmol Publications PVT. Ltd., 1999
Buku Referensi
Shah, Giraraj, author
Anmol Publications PVT. Ltd., 2000
Buku Referensi
Fry, Earl H., author
McGraw-Hill, 1983
Buku Teks
Jack Kitaeff, editor
Routledge, 2011
Buku Teks
Runturambi, Arthur Josias Simon, author
2013
Artikel Jurnal