Reference note fields:

Reference note fields lead from one classification number to one or more other classification numbers. A reference note field is used when more complex reference instruction is needed than can be conveyed by one or more simple cross references generated from 453 and/or 553 tracing fields .

There are two types of reference note fields:

see references (field 253 ), which refer to a classification number in another record

see also references (field 353 ), which guide the user to related topics in other valid classification numbers

Cross reference displays constructed from the reference note fields are complex cross references . Complex cross references are carried directly in records as reference note fields.