I honestly don't know the policy on this, but too many links within your content will make your article look odd and the reader may find it queer (especailly if the links are not really related to the content). I have used 3-4 links at the most and they were directly related to what I was talking about but they were spread out. I believe that when we are not professionals to what we are writing (e.g. I wrote about how people become killers) we need to back up what we say by using links referring to what we've said. Hope I've answered your question.