Battiston, Stefano and Puliga, Michelangelo and Kaushik, Rahul and Tasca, Paolo and Caldarelli, Guido  DebtRank: Too Central to Fail? Financial Networks, the FED and Systemic Risk.  (Nature) Scientific Reports, 2 (541).  pp. 1-6.  ISSN 2045-2322      (2012)