863-865 Subfield $w - Break indicator:
Subfield $w contains a one-character code that indicates the reason for a break in the enumeration and chronology.
A break in the enumeration and chronology contained in multiple 863-865 fields is due either to published issue(s) lacking in the collection or to unpublished parts or a lack of continuity in the enumeration and chronology of the parts. Subfield $w is contained in the Enumeration and Chronology field that represents the holdings that immediately precedes the break. The use of subfield $w requires a new field 863-865 in which the enumeration and chronology following the break is recorded.
g - Gap break: Code g indicates that part(s) are lacking in the holdings of the reporting organization. Code g is also used when there is doubt as to the cause of the break or when the cause is not known.
Example:
853 03 $81$aBd.$i(year)
863 40 $81.1$a1-19$i1911-1920/1921$wg
863 41 $81.2$a22$i1924/1925
[A gap occurs in the holdings between v.19 and v.22.]
n - Nongap break: Code n indicates that the break is due to unpublished part(s) or a lack of continuity in the enumeration and chronology of the parts.
Examples:
853 20 $81$a(year)
863 40 $81.1$a1900-1915$wn
863 40 $81.2$a1917-1940
[The holdings record contains no Enumeration and Chronology field for the nonpublished pieces. The nongap break is indicated by the code in subfield $w in the 863 field immediately preceding the break.]
853 20 $81$av.$i(year)
863 40 $81.1$a1-3$i1958-1960$wg
863 40 $81.2$a5-7$i1962-1965$wn
863 44 $81.3$a9-10$i1967-1968$wg
863 40 $81.4$a13-14$i1971-1972
[The reporting organization lacks volumes 4, 8, and 11-12. The second and third Enumeration and Chronology fields reflect both a nongap (v. 9-10) and a gap break (v. 11-12).]
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