If you are stuck, brainstorm for ideas that may help to solve your problem. Just write down ideas as they come to you. Don't worry about how practical they are, whether the records are accessible, how you will perform the search, etc. Just make lists of ideas. Don't research. Stay off the internet. Do not open a book. Just work on your list.
Then when you've exhausted yourself, start working on determining which ideas are practical and how those are best carried out. That's when you get back to researching, looking at sources, etc.
Brainstorming is best done when you don't distract yourself by doing research in the middle of it.