$PowerShares National AMT-Free MuniBd ETF(PZA)$ 8-K - Current report Filed: 2006-09-06 AccNo: 0001193125-06-185645 Size: 457 KBItem 1.01: Entry into a Material Definitive AgreementItem 7.01: Regulation FD DisclosureItem 9.01: Financial Statements and Exhibits 网页链接