N. K. Ratha, J. H. Connell, and R. M. Bolle, A biometrics-based secure authentication system, Proc. of IEEE Workshop on Automatic Identification Advanced Technologies (AutoId 99), pp.70-73, 1999.

S. Santesson, M. Nystrom, and T. Polk, Requests for Comments (RFC) 3739, Internet X.509 Public Key Infrastructure: Qualified Certificates Profile, The Internet Engineering Task Force (IETF), 2004.

R. Housley, Requests for Comments (RFC) 3852, Cryptographic Message Syntax (CMS) , The Internet Engineering Task Force (IETF), 2004.

P. Hoffman and J. Schaad, Requests for Comments (RFC) 5911, New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIME, The Internet Engineering Task Force, 2010.