506 RESTRICTIONS ON ACCESS NOTE (R)Indicators - Both undefined; each contains a blank (^)Subfield Codes $a Terms governing access (NR) $b Jurisdiction (R) $c Physical access provisions (R) $d Authorized users (R) $e Authorization (R) $u Uniform Resource Identifier (R) $3 Materials specified (NR) $5 Institution to which field applies (NR) $6 Linkage (NR) $8 Field link and sequence number (R)