Green, John, 1977-, author
Gramedia Pustaka Utama, 2022
Buku Teks
Grayson, Leslie E.
John Wiley & Sons, 1981
Buku Teks
Grayson, James Huntley
New York : Routledge Curzon, 2005
Buku Teks
Sharp, Walter R.
Rinehart, 1944
Buku Teks
Oates, John, author
Blackwell , 2004
Buku Teks