Identifying influential spreaders in complex networks Maksim Kitsak, 1, 2 Lazaros K. Gallos, 3 Shlomo Havlin, 4 Fredrik Liljeros, 5 Lev Muchnik, 6 H. Eugene Stanley, 1 and Hern´ an A. Makse 3 $^{1}$Center for Polymer Studies and Physics Department, Boston University, Boston, Massachusetts 02215, USA $^{2}$Cooperative Association for Internet Data Analysis (CAIDA), University of California-San Diego, La Jolla, California 92093, USA $^{3}$Levich Institute and Physics Department, City College of New York, New York, New York 10031, USA $^{4}$Minerva Center and Department of Physics, Bar-Ilan University, Ramat Gan, Israel $^{5}$Department of Sociology, Stockholm University, S-10691, Stockholm, Sweden $^{6}$Information Operations and Management Sciences Department, Stern School of Business, New York University, New York, New York 10012, USA (Dated: October 5, 2011) 1 arXiv:1001.5285v3 [physics.soc-ph] 4 Oct 2011