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Mary H. Munroe (2004). "Cambridge Information Group Timeline". The Academic Publishing Industry: A Story of Merger and Acquisition. Archived from the original on October 20, 2014 – via Northern Illinois University.
Fitzpatrick, Sean (January 8, 2011). "ProQuest acquires ebrary". American Libraries. Archived from the original on March 5, 2012. Retrieved February 3, 2012.
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