Tocci, Ronald&nbsp;J., Neal&nbsp;S. Widmer, Rosni&nbsp;Abu Kassim., Nooritawati&nbsp;Md Tahir., and  Yahaya Ramli. <em>Sistem digit</em>. Includes index. Edisi ke 8 edition. Petalilng Jaya, Selangor: Prentice Hall, 2003.