Association of Research Libraries Report (US)

Association of Research Libraries Report called Appraising our Digital  Investment: Sustainability of Digitized Special Collections in ARL Libraries:

http://www.arl.org/bm~doc/digitizing-special-collections-report-21feb13.pdf

Building on previous research that defined key aspects of sustainable digital content, the report offers a first look at the practices, attitudes, costs, and revenues associated with caring for digitized special collections. The report shares results from a survey conducted on the sustainability of digitized special collections at ARL member institutions.

Other ARL reports can be found here:

http://www.arl.org/publications-resources/search-publications/term/summary/47