Definition:
Scholarly/Academic sources are books, articles, and other types of documentation that have been published by experts in the field. They are generally "peer-reviewed" and published by reputable academic publishers.
Rationale:
Using these types of sources gives you, the author, the best possible information available so that your paper is of the highest quality. It also makes your professors happy!
Here are some tips and strategies for getting through this sometimes-dense academic material - material that is often outside of your realm of expertise (major) and comfort level.
Here are a few links to some sources you might find helpful in analyzing your museum/memorial.
Searching WISE is also useful for more in-depth, scholarly resources. Especially if you aren't quite sure where to go first.