NED and SIMBAD Conventions for Bibliographic Reference Coding
M. Schmitz (1), G. Helou (1), P. Dubois (2),
C. LaGue (1), B. Madore (1), H. G. Corwin Jr. (1) & S. Lesteven (2)
(1) Infrared Processing and Analysis Center, Jet Propulsion
Laboratory, CALTECH, Pasadena, CA 91125, USA
(2) CDS, Observatoire astronomique de Strasbourg,
11 rue de l'Université, 67000 Strasbourg, France
Published in "Information & On-line Data in Astronomy",
D. Egret & M.A. Albrecht, Eds., Kluwer Acad. Publ. (1995), p. 259.
History
The uniform 19-digit code used for bibliographic references within
NED and SIMBAD was developed by both teams in consultation
with Dr. H. Abt, editor of the Astrophysical Journal.
The primary purpose of the ``REF_CODE'' is to provide a unique
and traceable representation of a bibliographic reference within the
structure of each database.
However, in many cases, the code has sufficient information
to be quickly deciphered by eye, and it is used frequently in the
interfaces as a succinct abbreviation of a full bibliographic reference.
Since its inception,
it has become a standard code not only for NED and SIMBAD, but - with minor
variations - for ADS and
other bibliographic services. In addition,
the acronyms for journals used as part of the
code have become standards for some of the main
astronomical journals in
their own bibliographies.
Our main consideration in designing the REF_CODE was to make
its definition as objective as possible. This helps to avoid having
the history of data entry affect the naming system; allows automatic
coding to some extent; avoids confusion, conflicts, and ambiguities
in its meaning; lets different individuals or teams
construct REF_CODEs without having to resort to constant
consultation on the details of the code; and facilitates exchange
between databases (e.g. NED and SIMBAD).
The standard code is a string 19 characters long, a combination of
fields, some numerical and some alphabetic, exactly predictable for
journal articles, but not necessarily for books. The format is as
follows, with the various fields explained below. Blank spaces within
the string are replaced with periods, and no leading zeros are allowed in
volume and page numbers.
YYYYJJJJJVVVVMPPPPA
- YYYY:
- The four digits of the year of publication.
- JJJJJ:
- Code for the publication, entered left-justified within the
five spaces. Five categories are distinguished:
- Periodicals
- Periodicals (including both regularly-published periodicals
and occasional
publications): these codes are acronyms based on the names (as in ApJ,
A&A, PASJ, MNRAS), and are reserved for all years.
The codes for the journals that NED presently scans directly are given in
Table 1.
Codes for journals currently scanned for the SIMBAD bibliography
are given
in Table 2, and a sample of codes
for less-frequently encountered journals
are given in Table 3.
A complete listing of these tables is available
on the World-Wide Web, on the
NED and
SIMBAD servers.
- Catalogs:
- Catalogs these codes are generally built from ``standard''
abbreviations of the catalogs' names. Examples are UGC, ESO,
RSA, and RC3. If the catalog is a multi-volume work,
the volume number is inserted in the Volume field (see below).
The codes for some often-used extragalactic catalogs are listed
in Table 4.
- Books
- Books (by which we mean all other monograph-length
publications):
the codes in this category are constructed in essentially the
same way as those for periodicals and catalogs, from some or all of the
initials (or following letters) of the title.
While there is clearly some freedom in assigning codes to books, it is not
necessary for the user to be able to identify a random book from its
reference code (the database
interface does the decoding as needed). Note also that the same code
combined with a different year points to a different book.
- Theses
- thesis (primarily doctoral theses, but occasionally includes
masters theses): these codes are acronyms based on the name of the
university granting the degree
(see Table 5 for examples; the complete list
is available on-line). For theses, the volume number field (``VVVV''
below) contains ``.T00''. In the case of duplicate author initials, the
``.T00'' becomes ``.T01'', ``.T02'',
- Unpublished:
- this, unfortunately, is unavoidable as a category.
If the
reference is to a collection of data never described in print, then this
field will contain the code ``UNPUB''. Private communications to NED
or SIMBAD carry the code ``PrivC''.
- VVVV:
- Volume number, right-justified, if the reference is to a
periodical; otherwise, the second character in this field is a letter
that serves as a classification flag. The following flags and classes of
books are presently identified:
- B
- textbook
- C
- catalog
- M
- digitized version (magnetic tape, CD-ROM, etc.)
- P
- preprint
- R
- report or conference proceeding
- S
- symposium
- T
- thesis
- U
- unpublished
For multi-volume books, catalogs, and reports, the volume number is
given in the last two digits.
- M:
- This field is intended to break any remaining ambiguity after volume
number, page number, and author's initial have been specified. It is used only
when necessary, as in the following two classes of problems:
One class of
ambiguities results when there are two or more independent page sequences
within the same volume number, in which case the following codes are
reserved for this field:
- L
- Letters sections in various journals
- p
- Pink pages in MNRAS
- a, b, ..., z
- Issue numbers within the same volume, each of which
starts with page 1 (e.g. Physics Today).
- A, B, ..., K
- Issue designations used by publisher within same volume,
where each issue starts. with page 1.
Another class of ambiguities results when there are two or more
articles on the same page, as in Nature.
Such articles starting on the
same page are numbered sequentially in their order of appearance,
and a code corresponding to this order is inserted in
this field.
In that case, the code has values
- Q, R, ..., Z
- First, second, ..., tenth article on the page.
For Theses, this field contains the author's
first initial.
- PPPP:
- Page number of reference, or ``...0'' when the whole
book is
referenced. This field contains the page numbers, which are right-justified
within the four spaces available, preceded by periods to fill empty spaces.
- A:
- This field contains the first letter of the first author's last
name. This provides some redundancy in the code which might be useful in
tracking down errors. If the first author cannot be identified, or no
authorship is expressed, a colon (:) appears in this field. When the
REF_CODE as a whole does not follow the standard rules described above
(which might happen for books) a percent sign (%) is inserted in this
field. This field is case sensitive.
Here are some examples to illustrate the use of the reference code:
1983ARA&A..21..177S Stein and Soifer. 1983, Ann. Rev. Astron.
Astrophys. 21 177.
1988ApJ...324..767W Ward et al. 1988, Astrophys. J. 324 767.
1988ApJS...66..183J Jura. 1988, Astrophys. J. Suppl. 66 183.
1988PASP..100..625S Sandage. 1988, Publ. Astron. Soc.
Pacific 100 625.
1988Natur.331.6157B Bergvall. 1988, Nature 331 6157.
1976ApJS...31..187D Dressel and Condon. 1976, Astrophys. J
Suppl. 31 187.
1978IAUC.3305....1K Kowal, Lo, and Sargent. 1978, IAU Circ
No. 3305
1988A&A...206L..23M Maurogordato et al. 1988, Astron
Astrophys. 206 L23.
1984IRSD..R....118G Gatley. 1984, in Lab. and Obs. IR Spectra of IS Dust
proc. of the Hilo Workshop, July 1983, ed.
Wolstencroft and Greenberg, p. 118.
1909UCB...T00E....F Fath, E. A. 1909, The Spectra of Some
Spiral Nebulae and Globular Star Clusters
thesis, Univ. of Calif., Berkeley.
The Bibliographic Reference Code is a domain-specific code which was designed
to be sufficient for the immediate needs of
astronomy in uniquely, succinctly, and informatively
identifying bibliographic references. Nevertheless, the
REF_CODE proved to be general enough to encompass most
of the existing astronomical literature.
But these REF_CODEs were not
explicitly designed to be so general that they were guaranteed to
automatically encompass all presently available media, nor do they
necessarily fully anticipate future directions in publishing.
In combination with a descriptive reference database, the
cryptic form of the REF_CODE can be (and is) attached to a more extensible
information listing. For instance, while the REF_CODE carries
only the first page number of a reference, the Reference Database
carries the first and last page numbers of the article. Obviously, the same
qualifications apply to titles and authors which are highly
abbreviated in the REF_CODE, but more fully represented in the
Database.
The same principles could be used to fully link a REF_CODE
to data cubes, CD-ROMs, external databases, animations,
simulations, time-tagged data, etc. While the Reference Code is
compact, it is not yet saturated; there are still fields with
room for added pointers to the new directions that the publishing of
astronomical data may take in the immediate future.
We thank Helmut Abt and the rest of the NED and SIMBAD groups
for their help in defining the reference codes.
Table 2 has been prepared
with the kind help of Suzanne Laloë at
the Institut d'Astrophysique de Paris.
NED is a research support program operated by the
Jet Propulsion LaboratoryJPL,
California Institute of Technology,
under contract with the National
Aeronautics and Space Administration (Astrophysics Division, Science
Operations Branch). SIMBAD is maintained by the Centre de Données
astronomiques de Strasbourg, France.
question@simbad.u-strasbg.fr