\usepackage[utf8]{inputenc}
will not work for a bibliographic entry such as this:
@ARTICLE{Hardy2007,
author = {Ibn Taymiyyah, Aḥmad ibn ʿAbd al{-}Halīm},
title = {Naqḍ al{-}manṭiq},
shorttitle = {Naqḍ al-manṭiq},
editor = {Ḥamzah, Aḥmad},
publisher = {Maktabat a{l-}Sunnah},
address = {Cairo},
year = {1970},
sortname = {IbnTaymiyyaNaqdalmantiq},
keywords = { Logic, Medieval}}
For this entry use \usepackage[utf8x]{inputenc}