Error - DOI Naming Authority [nrg] Not Found

The DOI you requested --

nrg/journal/v9/n6/full/nrg2393.html

-- cannot be found in the Handle System.

Possible reasons for the error are:

• the DOI has not been created
• the DOI is cited incorrectly in your source
• the DOI does not resolve due to a system problem

If you believe you have requested a DOI that should be found, you may report this error by filling out the form below: