National Institute of Standards and Technology (NIST)
Fipsp: Authentication Technology Alternatives
These guidelines describes the primary alternative methods for verifying the identities of computer system users, and provides recommendations toFederal agencies and departments for the acquisition and use of technology which supports...
Other
Wfp Consulting: Si Navigator
A commercial site which has links to many SI/metrics sites. It gets you to a host of sites. Don't hesitate to use it for research.