Withington, Frederic G.
John Wiley & Sons, 1972
Buku Teks
Ogg, Frederic Austin, 1878-1951
Appleton-Century-Crofts, INC, 1952
Buku Teks
Lutz, Vera
Oxford University Press , 1962
Buku Teks
Osmond, Warren G.
Allen and Unwin, 1985
Buku Teks
Krop, Frederic Jean
Roelants, 1945
Buku Klasik