inda Gask, Bulent Coskun, David Baron
Wiley- Blackwell, 2011
Buku Teks
Gordon, Gary R. , author
Elsevier, 2012
Buku Teks
Conway, Mary E., author
Appleton , 1983
Buku Teks
Progress Publishers, [date of publication not identified]
Buku Referensi
Croom Helm, 1983
Buku Teks