edited by John Canning
Taplinger, 1967
Buku Referensi
Goldstein, Jan, author
Bhuana Ilmu Populer, 2004
Buku Teks
Niven, David, author
HarperCollins, 2003
Buku Teks
Moore, John Hammond, author
John Wiley & Sons, 1982
Buku Teks
Ferraby, John, author
Baha'i, 2011
Buku Teks