Steingass, F., author
Kegan Paul, Trench, Trubner & Co., 1947
Buku Referensi
Scharfstein, Zevi, author
America : Shilo Publishing House, 1073
Buku Referensi
Wandelt, Ingo, author
Friedrich Ebert Stiftung Indonesia Office, 2009
Buku Referensi
World Publishing Co, 1956
Buku Referensi
London: Tiger Books International, 1994,
Buku Referensi