. Author manuscript; available in PMC: 2014 Mar 3.
Published in final edited form as: Int J Impot Res. 2009 Jun 25;21(6):348–355. doi: 10.1038/ijir.2009.28
Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms