Lip, Evelyn, author
Times Books International, 1979
Buku Teks
War Departement, 1944
Buku Referensi
Wendy Abraham, author
John Wiley & Sons, 2013
Buku Teks
Purcell, Victor, 1896-1965, author
Oxford University Press, 1967
Buku Teks
Bushell, Stephen W., author
Wyman and Sons, 1906
Buku Teks