[Code of Federal Regulations] [Title 26, Volume 20] [Revised as of April 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 26CFR601.507] [Page 107] TITLE 26--INTERNAL REVENUE CHAPTER I--INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) PART 601_STATEMENT OF PROCEDURAL RULES--Table of Contents Subpart E_Conference and Practice Requirements Sec. 601.507 Evidence required to substantiate facts alleged by a recognized representative. The Internal Revenue Service may require a recognized representative to submit all evidence, except that of a supplementary or incidental character, over a declaration (signed under penalty of perjury) that the recognized representative prepared such submission and that the facts contained therein are true. In any case in which a recognized representative is unable or unwilling to declare his/her own knowledge that the facts are true and correct, the Internal Revenue Service may require the taxpayer to make such a declaration under penalty of perjury. [56 FR 24009, May 28, 1991]