Easton, Stewart C., author
Holt, Rinehart and Winston, 1955
Buku Teks
Hoyt, Robert S., author
Harcourt, Brace & World, 1966
Buku Teks
Painter, Sidney
Alfred A. Knopf, 1961
Buku Teks
Kirchner, Walther
Barnes & Noble. INC, 1968
Buku Teks
general editor, H.R. Loyn
Thames and Hudson, 1991
Buku Referensi