Brent, Nancy J., author
W.B.Sounders company , 2001
Buku Teks
Brent, Nancy J., author
W.B. Saunders, 2001
Buku Teks
Wood, William
Percival Marshall, 1949
Buku Teks
Williams, David, author
Sweet & Makwell, 2000
Buku Teks
Sinauer Associates, 1977
Buku Teks