754 ADDED ENTRY--TAXONOMIC IDENTIFICATION (R)Indicators - Both undefined; each contains a blank (^)Subfield Codes $a Taxonomic name (R) $c Taxonomic category (R) $d Common or alternative name (R) $x Non-public note (R) $z Public note (R) $2 Source of taxonomic identification (NR) $6 Linkage (NR) $8 Field link and sequence number (R)