A “citation number” has been added to the recommended way to cite AGU articles published in 2002 and later. This addition is necessary so that the Institute of Scientific Information (ISI) can count the number of times specific articles are cited.
The AGU “citation number” is a 4-digit number that will be assigned at the time of publication; i.e., when an article is posted online. For contributions, the numbers will be sequential throughout the year within a journal or section of JGR. Special issue papers will be numbered sequentially but in a different series. The new citation number is used in addition to the DOI (Digital Object Identifier). See www.agu.org/pubs/e_publishing/index.html?anchor = diff for further discussion of AGU's use of the DOI.