The Prevalence and Cost of Unapproved Uses of Top-Selling Orphan Drugs Kesselheim, Aaron S. ; Myers, Jessica A. ; Solomon, Daniel H. ; Winkelmayer, Wolfgang C. ; Levin, Raisa ; Avorn, Jerry Abstract Publication: PLoS ONE Pub Date: February 2012 DOI: 10.1371/journal.pone.0031894 Bibcode: 2012PLoSO...731894K