Schofield, John, author
Yale University Press, 1994
Buku Teks
McColvin, Eric, author
Longmans, Green and Co., 1946
Buku Teks
Gluck, Peter L., author
Rockport Publishers, 1997
Buku Teks
Marcucci, Luisa, author
Studio Books , 1960
Buku Referensi
O`Sullivan, Jeremiah Francis, 1903-, author
Appleton Century Croffs, 1943
Buku Teks