"[Citation] means that Google Scholar has not been able to find a source for the publication, but that it has inferred that it exists because other publications cite it.
Taken directly from Google Scholar help “These are articles which other scholarly articles have referred to, but which we haven’t found online. To exclude them from your search results, uncheck the “include citations” box on the left sidebar.”"
So basically the example you gave is an article that google scholar has fetched from the journal site. The [citation] links are from references of other articles.
If your articles are not in Google scholar, make sure that the gs plugin and the dublin core plugin is enabled. Also enabling google webmaster tools and sending your OJS sitemap to Google is probably a good idea, see [OJS 2.3.1.2] Indexing journal system to Google Scholar