Saint-Laurent, George E.
Mayfield, 2000
Buku Teks SO
Ferraby, John
Baha'i, 2011
Buku Teks SO
Pius Suratman
1986
UI - Tesis Membership
edited by Stewart Sutherland, Leslie Houlden, Peter Clarke, Friedhelm Hardy
Routledge, 1988
Buku Referensi
Smith, Wilfred Cantwell
Mizan , 2004
Buku Teks SO