Rujukan Nombor_pengenalan_peribadi

  1. ↑ Higgs, Edward (1998). History and Electronic Artefacts. Oxford University Press. ISBN 0198236336. 
  2. ↑ Martin, Keith (2012). Everyday Cryptography: Fundamental Principles and Applications. Oxford University Press. ISBN 9780199695591. 
  3. ↑ Cale, Stephane (2013). Mobile Access Safety: Beyond BYOD. Wiley Publishing. ISBN 978-1-84821-435-4. 
  4. ↑ "E-Commerce: A Tangled Web for PIN Debit". Digital Transactions. 1 February 2013 – melalui Associated Press.