Ahuja, B. N., author
Surjeet Publications, 1989
Buku Teks
Berita Publishing Sdn Bhd, 1993
Buku Referensi
Tomlinson, Henry Major, author
Heinermann, 1930
Buku Teks
Clark D. Moore and Ann Dunbar
Praeger Publishers, 1968
Buku Teks
Langland, William, author
Phoenix House, [1959]
Buku Teks