Make a list of the key words that might be associated with your problem cases.
In your list of keywords Include:
the names of particular problem cases -- these keywords are terms used in the concrete description of the problem case you developed in the Focus phase.
general topics of discussion -- these are general terms related to the topic. For example, when you look at the "key words" of a journal or conference article, these are the general topics key words.
any authors you may have heard or read about -- keep track of all the authors you have written about the issue. This is a great way to find both new and old work and find other people involved in the debate.