Neimark, Edith D., author
Harcourt Brace Javanovich, 1987
Buku Teks
Whitehead, Alfred North, 1861-1947, author
The New American Library, 1933
Buku Teks
Gallup, George, author
McGraw-Hill, 1982
Buku Teks
edited by Matthew Beaumont
Blackwell, 2007
Buku Teks
Boissonneau, Alice
Simon & Pierre Pub. Co. , 1976
Buku Teks