Stone, Richard
Blackstone Press limited, 1997
Buku Teks
Fortin, Jane, author
Cambridge University, 2005
Buku Teks
Quesne, Terence Du
Hx Heterodox, 1986
Buku Teks
Fulton, Rorie, author
Learning Matters, 2011
Buku Teks
Cexhead, Elizabeth
Longmans Green, 1961
Buku Teks