Graves, Robert, author
Macmillan, 1943
Buku Referensi
Chambers, R.W. (Robert Warner), author
Oxford University, 1950
Buku Teks
FitzGerald, Robert David, 1902-, author
Melbourne University Press, 1963
Buku Teks
Holt, Rinehart and Winston, 1969
Buku Teks
Australian National University Press, 1975
Buku Teks