Association of Research Libraries and ARL Office of Leadership and Management Services, and Online Computer Library Center (OCLC). 1999 ARL/OCLC Strategic Issues Forum. The Keystone Principles http://www.arl.org/training/keystone.html
Auer, Nicole. Bibliography on Evaluating Internet Resources
COUNTER http://www.projectCounter.orgIn order to measure the use of online resources in a more consistent way, COUNTER is an agreed to international Code of Practice governing the recording and exchange of online usage data.