What is the educational goal of such an assignment?
Certainly researchers and graduate students need to perform literature searches to understand the state of the art (as well as the research frontier) and also to uncover related work (so-called "novelty" being important for publication, etc.)
But for most of K-12, isn't the subject matter fairly well established and written up in a more useful, tutorial format, in textbooks?
I suppose there could be exceptions, perhaps current events or popular culture, or maybe developments in particularly fast-moving fields. But in this case I think students would be well served by a curated collection of sources rather than being cast off in the deep end without guidance. If the goal is to expose students to primary sources (which can be very interesting) I think a curated collection would also work well.
Encyclopedias are great though, for both random and focused reading. Both subject-based and alphabetic organization can be good for browsing and discovery.