Hagen, O. A. (2010). Digital books: Competition and commerce. Nova Science Publishers.
Chicago Style (17th ed.) CitationHagen, Oliver A. Digital Books: Competition and Commerce. New York: Nova Science Publishers, 2010.
MLA (9th ed.) CitationHagen, Oliver A. Digital Books: Competition and Commerce. Nova Science Publishers, 2010.
Warning: These citations may not always be 100% accurate.