Projected date of publication used in bibliographic records for works that have not yet
been published.
Indicators
First - Undefined
# - Undefined
Second - Undefined
# - Undefined
Subfield Codes
$a - Projected publication date (NR)
Six-digit date recorded in the pattern yyyymm (4 digits for the year; 2
digits for the month). A hyphen (-) is used for an unknown portion of the
date.