The Bottom Line: Scholarly sources are written by experts for experts, and they’re the only kind of sources that belong in your poster and literature review. Substantive sources — like serious magazines or trade publications — and popular sources — like news, blogs, or general websites — can still be useful in your preliminary reading. They can help you get oriented and build background knowledge. But when it comes to your deliverables, the expectation is clear: your evidence and analysis must come from scholarly sources.