See the work of Sir Paul Collier, Havard Hegre, Anke Hoeffler, Marta Reynol-Querol, Nicholas Sambanis and T. David Mason. Following on from the work led by Collier during his tenure as its Director, the World Bank's Economic Research office has made substantive contributions. See in particular an Oxford Economics Papers article by Collier and Hoeffler in either 2003 or 2004.

Thanks V. L Elliott