Martinez, Julio A.
Greenwood Press, 1985
Buku Teks
Duke University Press,
Majalah, Jurnal, Buletin
Short, Raymond W., author
Henry Holt and Company, 1954
Buku Teks
Wachner, Clarence W., author
Macmillan, 1963
Buku Teks
Holman, C. Hugh, author
Macmillan, 1986
Buku Referensi