The Narcissistic Personality Inventory (NPI) was developed in 1979 by Raskin and Hall and it has become one of the most widely used personality measures for non-clinical levels of the trait narcissism.<ref name=":0">{{Cite book|title=The handbook of narcissism and narcissistic personality disorder : theoretical approaches, empirical findings, and treatments|date=2011|publisher=John Wiley & Sons|others=Campbell, W. Keith., Miller, Joshua D.|isbn=9781118093108|location=Hoboken, N.J.|oclc=784135838}}</ref> | The Narcissistic Personality Inventory (NPI) was developed in 1979 by Raskin and Hall and it has become one of the most widely used personality measures for non-clinical levels of the trait narcissism.<ref name=":0">{{Cite book|title=The handbook of narcissism and narcissistic personality disorder : theoretical approaches, empirical findings, and treatments|date=2011|publisher=John Wiley & Sons|others=Campbell, W. Keith., Miller, Joshua D.|isbn=9781118093108|location=Hoboken, N.J.|oclc=784135838}}</ref> |