Lindeman, Ralph D
Twayne Publishing, 1965
Buku Teks
[Canberra] Angus & Robertson 1989,
Buku Referensi
Greenlees, Duncan
The Theosophical Publishing House, 1952
Buku Teks
Reinecke, Ian
Mcphee Gribble Publishers, 1985
Buku Teks
Cross, Ian
Whitcombe and Tombs, 1972
Buku Teks