Wikipedia contains many information about million of topics but each single thematic page doesn’t contain all the possible info or links about that specific subject. In fact some other details about a topic, or related to it, can be in other parts of Wikipedia not linked to the main topic.
In my experience, sometimes you can find some really interesting details about a topic if you simply use a Google query as:
Where the topic is “Chet Baker” and it is searched by Google into the entire Wikipedia.org website. If you deeply peep the results you can now find some information not contained in the “Chet Baker” page in Wikipedia.