Boughey, Arthur S., author
Dickenson , 1967
Buku Teks
Panchen, Alec L., author
Cambridge University Press, 1994
Buku Teks
Macfadyen, A.
Pitman Publishing Corporation, 1963
Buku Teks
Southwood, T.R.E.
Chapman and Hall , 1968
Buku Teks
Gleich, Michael; Maxeiner, Dirk; Miersch, Michael; Nicolay, Fabian
Atlantic Monthly Press, 2002
Buku Referensi