863-865 $a-$h - Enumeration:
Subfields $a-$h contain the levels of enumeration that either appear on an item or that are used by the reporting organization to record the receipt of an item. These enumeration subfields are correlated with enumeration caption subfields $a-$h in the 853-855 Captions and Pattern field linked to the 863-865 field, although the same subfields need not always be present. Full correlation of the enumeration level and the caption subfields $a-$h in linked 853-855/863-865 fields is not required when captions are not desired for displaying the holdings statement. Full correlation is required when compression or expansion of the field 863-864 enumeration of computer algorithm is desired. If there is no enumeration on the item for some level, enumeration may be invented and enclosed in brackets ( [ ] ).
When alternative numbering schemes are applicable to an item, subfields $g and $h contain the alternative enumeration. If more than two levels of alternative enumeration are required, and 866-868 Textual Holdings field is used.
When only chronology is used on an item (that is, the item carried no enumeration ), the chronology is contained in the relevant enumeration subfield ($a-$h) instead of the chronology subfield ($i-$m). Example:
$b Second level of enumeration
$d Fourth level of enumeration
$g Alternative numbering scheme, first level of enumeration
$h Alternative numbering scheme, second level of enumeration
See also:
863-865 Enumeration and Chronology - General Information