Subscription databases, such as Academic Search Premier and JSTOR, are typically comprised of "peer-reviewed" or "scholarly" journal articles. In contrast, there is no overseeing authority that verifies information found freely on the web. Therefore, resources found in subscription databases accessed through your campus library tend to be more credible than those found through publicly available websites, such as Google and Yahoo.
There is merit in using resources from both subscription databases and publicly available websites. However, since publicly available sites are not verified by any source, self evaluation should be performed. Aspects to consider when evaluating a website are the domain (such as .edu, .com., .gov, etc.), the credentials of the author, the purpose of the website, and the date the information was published.
Many libraries, historical societies and centers for the study of history or literature offer access to digital collections online. You can locate these kinds collections with an internet search, using search terms like illuminated manuscripts, digital library, history of the book, a specific author or the specific title of a work you are researching (i.e. Book of Kells, Pride and Prejudice, Jane Austen).
Check out some of these online collections: