http://www.loc.gov/marc/relators/relators.html

The purpose of this list of relator terms and associated codes is to allow the relationship between a name and a work to be designated by codes in the MARC record.

http://www.loc.gov/marc/relators/relaterm.html

http://www.loc.gov/marc/relators/relacode.html

Según MARC:

$e - Relator term (R) Describes the relationship between a name and a work.

$4 - Relator code (R) A MARC code for the relationship between a name and a work.

Según OCLC:

‡4 Relator code: A three-character code that indicates the relationship of the entry to the item.

‡e Relator term: A designation of function that describes the relationship between a name and a work (e.g. collector, comp., defendant, ed., ill., joint author or tr.).

Blogs:

http://outgoing.typepad.com/outgoing/2006/10/relator_codes_a.html

http://kcoyle.blogspot.com/2006/11/relators.html

http://www.frbr.org/2006/11/08/relators

AACR2R:

21.0D Adición optativa. Designaciones de función 21.0D1

D. Fritz:

IsisMarc: