Documents from Osama bin Laden's compound in Pakistan show his training in public administration had a strong influence on al-Qaida, experts say. The material scooped up by the Navy Seal team that killed him last month includes years of receipts, National Public Radio reported. Al-Qaida operatives were apparently supposed to bring receipts for even relatively small expenditures when they returned to headquarters. Lt. Col. Reid Sawyer, director of the Combating Terrorism Center, said the meticulous record-keeping, in addition to being a product of bin Laden's undergraduate training, was probably necessary. He said operatives were scattered and often unable to keep in touch with headquarters regularly. "It's this idea that when you have a distributed movement, that you have to gain efficiencies in various means," Sawyer said. "And one way to do that is to keep very good records and to understand the disparate parts of your enterprise." The United States found an earlier trove of al-Qaida documents in 2003. They were in safe houses in Afghanistan.