Banks, J. A.
Routledge & Kegan Paul Limited, 1954
Buku Teks SO
edited by Patrick Brantlinger and William B. Thesing
Blackwell, 2002
Buku Referensi
Bryant, Arthur
The Albatross MCMXL.VII, 1947
Buku Teks SO
Cronin, James E.
Routledge, 1991
Buku Teks SO
Mathias, Peter
Methuen , 1979
Buku Teks SO