Reference heading:

An unestablished name or subject in a traced or untraced reference record. The record containing a reference heading also contains either a 260 (Complex See Reference - Subject) , a 664 (Complex See Reference - Name) , or a 666 (General Explanatory Reference - Name) field to guide the user to the established form. Separate codes are defined in 008/09 for traced (code c ) and untraced (code b ) reference records. The distinction depends upon whether the heading in the 1XX field in the record is also given as a 4XX See From Tracing in another authority record for traced and untraced.