From NSDLWiki

hasresourceUSER

The hasResourceUSER property identifies agents that represent an individual.

Namespace 

http://ns.nsdl.org/api/relationships#

Prefix 

nsdl

Cardinality 

exactly one

Found in 

Agent

Values 

NSDL login username

Usage and Semantics

• Value is assumed to be a valid NSDL login identifier (from NSDL LDAP), or equivalent
• Unique repository-wide.