500 GENERAL NOTE (R)Indicators - Both undefined; each contains a blank (#)Subfield Codes $a General note (NR) $l Library of Congress call number (SE) OBSOLETE $x International Standard Serial Number (SE) OBSOLETE $z Source of note information (AM SE) OBSOLETE $3 Materials specified (NR) $5 Institution to which field applies (NR) $6 Linkage (NR)