We study contracting for a three-tier supply chain consisting of a buyer, a supplier, and a sub-supplier where disruptions of random length occur at the sub-supplier. As is common in supply chains, the buyer has a direct relationship with the supplier but not the sub-supplier; that is, the buyer...

"Past research into the determinants of international trade highlighted the importance of the basic spatial gravity model augmented by additional variables representing sources of friction. Studies modeled many sources of friction using various proxies, including indices based on expert judgment...