A demographic and prognostic approach to defining the end of life
Journal of Palliative Medicine
http://online.liebertpub.com/doi/abs/10.1089/jpm.2005.8.s-12?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed