Wikoff, Karin. (2012). Electronic resources management in the academic library: a professional guide. Santa Barbara, California: Libraries Unlimited.
The book covers what a content provider is, "vendor, or a publisher, or any number of in-between agents" (pg. 11). It provides a definition of the role of aggregator as someone who picks and chooses data from different content providers and puts it all together in a neat package. The book goes in to the various ways of making the content available, using trials, evaluation, and keeping costs low.