Dust and the ultraviolet energy distribution of quasars
  The ultraviolet energy distribution of quasars shows a sharp steepening of the continuum shortward of 1000 A (rest-frame). We describe how we came to consider the possibility that this continuum break might be the result of absorption by carbon crystallite dust grains. 
Luc Binette, Christophe Morisset and Sinhue Haro-Corzo