Okay, if I’m being honest, there is no possible way I can
answer this question. My psychic powers have failed me. I don’t know what
research you’ve done nor how exhaustive it was. As a result, I don’t have any
idea what you might have missed.
As with any kind of research, the first thing you’re going
to want to do is start by identifying the core literature from the field. You can
do this by simply looking at the Wikipedia references, and then following up with those. (The actual Wikipedia articles are usually worthless for
research, but what the editors cited can be a valuable starting place.) Once
you’ve started reading those sources, see what multiple sources reference. If
someone’s worth talking about, then they’re probably worth reading. If no one’s
referencing what you’re starting with, then it may be a sign that the source isn’t really that important. If it is cited, it will either be important
information for the subject, or controversial. The tone of their
citations should tell you which.
While you’re doing that, keep track of who the respective
authors are. Those biographies slapped on the dust jacket are a good place to
start. You don’t need to know everything about them, but if you’re looking at
someone who spent decades in law enforcement or the intelligence community,
they’re probably more reliable and useful than a random fan of 47 who mostly
posts on Gamefaqs or a housewife from New Jersey publishing under a pseudonym.
Obviously, this will be easier if you’re in an academic
environment, and have access to scholarly articles, though even without that,
the basic framework is solid. Though, you might have to hit an actual library
to find some of the material you need.
If you didn’t do any of that, then the answer will be, “a