Answered By: Martin Morris
Last Updated: Mar 14, 2017     Views: 680

Note: we recommend also reading our FAQ entry on the "Link Adjacent" operator.

When editing styles in Endnote, we use the forced separation operator (the "|" character) when we want to link punctuation to the field that follows it, and to ensure that the linked punctuation only appears when that linked field is populated.

A typical example is the volume number, which in most styles follows the issue number.

Let's consider an example.  Say our citation style requires the following punctuation:

  • (where we have both the issue (150) and volume (10) number)
    Ranganathan SR. (1933). The Five Rules of Library Science. Journal of Libraries, 150, 10. 120-127.
  • (where we have an issue number, but not a volume number)
    Ranganathan SR. (1933). The Five Rules of Library Science. Journal of Libraries, 150. 120-127.

Note that in both cases, we always want the Volume and Issue section of the citation to end with a period.  In the second example, we do not want the comma to appear if there is no issue number.

If we set up this style in the Endnote style editor as below... 

Volume, Issue.

...we will have a problem if the Issue field is empty. If both the Volume and Issue fields are populated, the style will output:

150, 10.

This is the desired output.  However, if the Issue field is empty, the style will output:


This is not our desired output, as we wish to remove the comma and replace it with a period.  To make the comma dependent on the following field (Issue), we use the forced separation operator, as follows:

Volume|, Issue|.

The comma has now been linked to the Issue field in the same section, and will now only appear if the Issue field is populated. The period is also preceded by a forced separation operator to break its connection from the previous Issue section. This section of the citation will now always appear with a period at the end, whether or not there is an issue number.

Note that the forced separation operator will not ensure that the Volume and Issue will always appear together on the same line of the citation.  To achieve this, we also need to use a Link Adjacent operator.