5Paula Kaufman, Sarah B Watstein. Library value (re- turn on investment, ROD and the challenge of placinga value on public services [J ]. Reference Senices Re- view, 2008, 36 (3): 226-231.
6K G. Remm on int (ROI) in German libraries, The Berlin School of Library and Information Science and the University Library at the Humboldt University, Berlin a case study [ J ]. The Bottom Line: Managing Library Finances , 2010, 23 (4): 141-201.