Gunston, Bill.
Patrick Stephens limited, 1995
Buku Teks
Conason, Joe, author
Simon & Schuster, 2016
Buku Teks
edited by S.H. Steinberg
Funk & Wagnalls, 1954
Buku Referensi
Williamson, Bill
Oxford Basil Balckwell 1990,
Buku Teks
Harvey, Clare G., author
Thorsons, 1995
Buku Referensi