Kingsland, William, author
George Allen and Unwin, 1954
Buku Teks
De Burgh, W.G. (William George), 1866-1943
Penguin Books, 1953
Buku Teks
edited by Delmer M. Brown
Cambridge University Press, 1993
Buku Referensi
Webster, Hutton, author
D.C. Heath, 1947
Buku Teks
Bagnall, Roger S.,
Routledge, 1995
Buku Teks