Singh, Baljit
Bombay Hind Kitabs Publishers 1947,
Buku Teks
Singh, Madanjeet
New York Graphic Society, 1956
Buku Referensi
Potten, A.J. van, author
Rabobank International Group, 1966
Buku Teks
Volwahsen, Andreas, author
Preste, 2001
Buku Teks
Artikel Jurnal