Ferguson, John C., author
Scammon Lectures, 1918
Buku Teks
Michell, George, author
Thames & Hudson, 2000
Buku Teks
edited by Diane Elizabeth Waller and Andrea Gilroy
Open University Press, 1992
Buku Referensi
general editor, Sir Lawrence Gowing
Encyclopaedia Britannica, 2005
Buku Referensi
general editor, Sir Lawrence Gowing
Encyclopaedia Britannica, 2005
Buku Referensi