Sometimes it's important to know how to search as well as what to look for and I've found it helps to do a little thinking before one begins the search.
For example, a couple of years ago a play producer was looking for the script of a play by a very reclusive playwright. Searches on all Search Engines had only yielded the curt message, "This person's contact information is private."
In desperation, he finally posted a plea on a playwrights' message board, hoping one of us may be a friend of that playwright.
None of us were but I got him access to a copy of the script in ten minutes flat, using a net search but not quite in the way he had.
Here's the logic I applied:
The producer has searched for the script and for the playwright and gotten nowhere. Therefore, searching for those items is non-productive.
The producer wants the script, not the playwright per se.
Who else will have the script? Or rights to sell it?
So I just googled "agent (playwright's name)" (without the quotes or brackets), got the name of the agent who represented the playwright and sent her contact information on to the producer. It took me five minutes. Within the next five the producer had contacted her and placed an order for the script.
Sometimes the information you want isn't visible on the net but it's accessible through people connected to the net. If you can't find "what", look for "who".