how to merge two paper of the same author in citation

I have to paper from the same author , for example,  Smith  2006a, and  2006b.

I want to use (Smith  2006a, b) in paper citation, but I only can get  (Smith  2006a, Smith  2006b) after I create new style

What can I do? I use Endnote X4.

BTW: I search the web and try to use Edit  reference from Word, and hide the author from the second paper, but I can only get  (Smith  2006a, 2006b), not exactly as what I want. If I hide the year of the second paper, then the second paper dispears.


When you edit the citation (Smith 2006a, Smith 2006b), for the first citation insert a comma followed by the letter b in the Suffix field (see Image1 - which uses Agresti as the author). Then for the second citation click to select “Year” then click OK to close the Edit & Manage Citations window (See Image2).