Hansen, Harry, author
A Mentor Book, 1961
Buku Teks
Pratt, Fletcher, 1897-1956, author
Pocket Books, 1948
Buku Teks
Hansen, Harry, author
A Mentor Book, 1961
Buku Teks
Svenson, Peter
Faber and Faber , 1994
Buku Teks
Roland, Charles P.
McGraw-Hill, 1991
Buku Teks