On the Use of Impredicative Reasoning to Construct a Class of Partial   Models of ZF Within ZF [Withdrawn]
  This paper has been withdrawn due to a critical error discovered in Theorem 4.21. Anyone with a historical or pragamatic interest in prior "negative results", however - e.g., failed proof attempts relating to the (in)consistency of ZF or the soundness of impredicative reasoning - is welcome to retrieve the original version of the paper still avaailable here on arXiv. 
Bryan Ford