“Should the United States or the international community aggressively pursue nuclear nonproliferation policies?” co-authored with Scott D. Sagan, in Peter M. Haas and John A. Hird (eds.), Controversies in Globalization: Contending Approaches to International Relations, 2nd Edition, Washington, DC: CQ Press, 2013.
“The Conundrum of Close Calls,” co-authored with Scott D. Sagan, in Henry D. Sokolski and Bruno Tertrais (eds.), Nuclear Weapons Security Crises: What Does History Teach?, U.S. Army War College, Strategic Studies Institute, 2013.
“History, Close Calls, and Nuclear Materials Security,” co-authored with Scott D. Sagan, commissioned by the Nuclear Threat Initiative for preparation of the Nuclear Materials Security Index 2.0, December 2012.