Nathan, Jacques
Paris F. Nathan 1952
Buku Referensi
New York : William Marsh Rice University
Majalah, Jurnal, Buletin
Alexandrova, Vera
New York Doubleday 1963
Buku Teks
Blamires, Harry, author
Longman, 1989
Buku Teks
Winnipeg : University of Manitoba
Majalah, Jurnal, Buletin