I'm having trouble finding any standard or documentation for the
construction of the variable parts of serials call numbers, that is to
say, the chronological and/or physical units within one bibliographic
record which follow the class and book (Cutter) numbers (referred to
at LC as the "small label".  These variables affect spine labels and
item records in an OPAC.  I have found nothing on the subject in
Library Literature.

I would appreciate hearing from anybody who knows of published
documentation, and from libraries who have their own in-house
guidelines.

The LC _Subject Cataloging Manual: Shelflisting_ does not adequately
deal with this issue (unless I am missing something).  G180 says to
use the "volume designation/numbering ... indicated by tag 362", but I
think that is potentially confusing (see below).  G1000 says that
"additional processing instructions for all periodicals can be found
in the Serials Unit Manual", which I assume has not been published for
public use.

The problems that I do not see addressed in the Shelflisting manual
(or elsewhere) are twofold:

1.  Hierarchy.  Call number structure is presumably hierarchical, with
each segment narrowing the definition of the previous segment.  The
use of the 362 field as a model for labelling items confuses the
hierarchical scheme, since (more often than not) the 362 designation
includes parallel/synonymous numeric and chronological designations.
Not only does the second element of the 362 (usually the
chronological) not narrow the definition of the previous element
(usually the numeric), but it clutters the limited space of a call
number label and OPAC item record with redundant information.
Choosing one designation over the other can be tricky since sometimes
it is the numeric designation which is visually and bibliographically
significant, and sometimes it is the chronological designation.

2.  Chronological part versus physical part.  This is the most
confusing detail for the library technicians charged with labeling
materials.  A part designation can be either chronological or it can be a
physical designation within a chronological part.  For example, "Vol.
4, 1994" can be a parallel designation wherein the numeric and
chronological both mean the same thing, or it can mean that the 1994
edition of a work is issued in at least four physical parts wherein
"vol. 4" further narrows the scope of "1994", or it can mean that the
item is the 1994 edition of vol. 4.  The truth of the matter is
normally evident from the bibrecord, but technicians often do
labelling in a routine mode without reference to the bibrecord.

This is a simplistic description of an area that can get very complex.
I have written an in-house manual section that requires 25 pages to
explain the complexities.  I am not comfortable with the idea that I
am pioneering this.  Shelf arrangement in many libraries would suggest
that they have sensibly addressed the issue, but I am at a loss to
find documentary evidence.

Any help would be most welcome (and especially from somebody familiar
with the LC "Serials Unit Manual").

T. F. Mills               tomills@du.edu  or  tomills@diana.cair.du.edu
University of Denver Library  2150 E. Evans Ave.  Denver  CO 80208  USA