Danbury : Lexicon Publications, Inc., 2004,
Buku Referensi
Danbury : Lexicon Publications, Inc., 2004,
Buku Referensi
The World Publishing Co., 1951
Buku Referensi
The World Publishing Co., 1951
Buku Referensi
Julius Groos Verlag, {s.a}
Majalah, Jurnal, Buletin