Arnold, Pauline
Holiday House , 1963
Buku Teks
Thorne, W.J.
Oxford University Press , 1948
Buku Teks
Bradford, Frederick A.
Longmans, Green, 1932
Buku Teks
Rodgers, Raymond
Alexander Hamiltion Institute, 1962
Buku Teks
Levin, Howard S.
John Wiley & Sons, 1956
Buku Teks