Bibcode

The bibcode (also known as the "refcode") is a compact identifier used by a number of astronomical data systems to uniquely specify literature references. The Bibliographic Reference Code (REFCODE) was originally developed to be used in SIMBAD and the NASA/IPAC Extragalactic Database (NED), but it became a de facto standard and is now used more widely, for example, by the NASA Astrophysics Data System who coined and prefer the term "bibcode". The code has a fixed length of 19 characters and has the form YYYYJJJJJVVVVMPPPPA where YYYY is the four-digit year of the reference and JJJJJ is a code indicating where the reference was published. In the case of a journal reference, VVVV is the volume number, M indicates the section of the journal where the reference was published (e.g., L for a letters section), PPPP gives the starting page number, and A is the first letter of the last name of the first author. Periods (.</tt>) are used to fill unused fields and to pad fields out to their fixed length if too short; padding is done on the right for the publication code and on the left for the volume number and page number. Page numbers greater than 9999 are continued in the M</tt> column. The 6-digit article ID numbers (in lieu of page numbers) used by the Physical Review publications since the late 1990s are treated as follows: The first two digits of the article ID, corresponding to the issue number, are converted to a lower-case letter (01 = a etc.) and inserted into column M</tt>. The remaining four digits are used in the page field. Some examples of the code are as follows: