?url_ver=Z39.88-2004&rft_id=10.1109%2FRSM.2013.6706495&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Ashraf%2C+K.&rft.aulast=Ashraf&rft.aufirst=K.&rft.isbn=9781479911837&rft.date=2013&rft.title=Frequency+dependence+of+quality+factor+in+vibration+energy+harvesting&rft.genre=proceeding