Bode, Boyd Henry
D.C Heath and Company, 1940
Buku Teks
Watchtower Bible and Tract Society, 2003
Buku Teks
Duhigg, Charles, author
Heinemann, 2012
Buku Teks
King, MArtin Luthre
Harper & Row pub, 1964
Buku Teks
Sinek, Simon, author
Penguin, 2017
Buku Teks