Stead, Christina
Angus & Robertson, 1974
Buku Teks
England, Alan
Macmillan Education, 1990
Buku Teks
Clapham, John, Sir, author
University Press , 1944
Buku Teks
Clapham, Alfred, Sir, author
Longman, Green, 1950
Buku Teks
Plumb, J.H. (John Harold), 1911-, author
Penguin Books, 1963
Buku Teks