$Ultra Petroleum(UPL)$ 8-K - Current report Filed: 2017-04-18 AccNo: 0001193125-17-127356 Size: 3 MBItem 1.01: Entry into a Material Definitive AgreementItem 1.02: Termination of a Material Definitive AgreementItem 2.03: Creation of a Direct Financial Obligation or an Obligation under an Off-Balanc 网页链接