Subfield $w/2 - Earlier form of heading:  [4XX and 5XX:  Tracing Fields - Simple Cross References]

Subfield $w/2 contains a one-character alphabetic code that indicates whether the heading in the 4XX field is an earlier form in which the name or subject was established either in the relevant national authority file or in an authority file other than the national authority file.

The codes are:

a - Pre-AACR 2 form of heading (national name authority file)

e - Earlier established form of heading (national authority file)

o - Earlier established form of heading (other authority file)

n - Not applicable

Precedence of Codes:

When more than one code applies to the heading in a 4XX field, the following table is used to determine the precedence status of each code.  Preference is given to codes higher on the lists.  The Names column covers records for names formulated according to descriptive cataloging rules.  The Subjects column covers records for subjects formulated according to subject heading system/thesaurus conventions.

To return:

Use the key.