Appendix H: 990 Link to Equivalences or Cross-References

-- Canada only --

Field 990 links equivalent and reference fields to their corresponding access fields. Each occurrence of field 990 links a separate equivalence or reference.

Field 990 is repeatable.

Specifications for Field 990:

Position	Description	Repeatability
Field 990 (Canadian)	Link to Equivalences or Cross-References	R
Indicator:
First	Type of link
0	Equivalence
1	Cross-reference

Second	Language of catalog
0	English
1	French

Subfield code:
$a	Link information for 9XX fields	R
$b	Link information for field corresponding to 9XX field	R

Subfields $a and $b are used to record the level numbers assigned according to the occurrence within each record of fields which have the same tag value. A new level number sequence begins with each distinct tag value. The data in subfields $a and $b is structured as follows:

Tag	Level	Contents of Field
700	01	1#$aBignell, Sharon.
700	02	1#$aVinson, Richard.
710	01	2#$aParkland Regional Arts Committee.
710	02	2#$aKnow Your Neighbour (Project) Stoney Plain, Alta.
900	01	1#$aVinson, Richard W.
910	01	2#$aOpportunities for Youth (Federal aid programme) Stoney Plain, Alta.
990		10$a90001a$b70002a
990		10$a91001a$b71002a

Multiple subfields $a and $b may occur in one field 990 when concatenated by an "and" condition, e.g., subfield $b can repeat to accommodate name/title combinations.

Examples:

Corporate main entry equivalence

110 2# $aBibliothèque nationale du Canada.

910 2# $aNational Library of Canada.

990 00 $a91001a$b11001a

Personal name cross-reference

700 1# $aClark, Marvin L.

900 1# $aClark, M.L.$q(Marvin L.)

990 10 $a90002aq$b70001a

Personal name/title equivalence

100 1# $aWagner, Richard,$d1813-1883.

243 10 $aSelections;$oarr.

900 1# $aWagner, Richard,$d1813-1883$tExtraits;$oarr.

990 01 $a90001adto$b10001ad$b24301ao