PUBLIC LAWS-CH. 120-JUNE 23,1947 Ante, p, I42. Ante, p. 143 . Access to evidence. Issuance of sub. penas. Administration of oaths, etc. Refusal to obey sub. pena, etc. party, shall be given an opportunity to appear by counsel and present any relevant testimony: Provided further, That for the purposes of this subsection district courts shall be deemed to have jurisdiction of a labor organization (1) in the district in which such organization maintains its principal office, or (2) in any district in which its duly authorized officers or agents are engaged in promoting or protecting the interests of employee members. The service of legal process upon such officer or agent shall constitute service upon the labor organization and make such organization a party to the suit. In situations where such relief is appropriate the procedure specified herein shall apply to charges with respect to section 8 (b) (4) (D). 4"INVESTIOATORY POWERS "SEo. 11 . For the purpose of all hearings and investigations, which, in the opinion of the Board, are necessary and proper for the exercise of the powers vested in it by section 9 and section 10- "(1) The Board, or its duly authorized agents or agencies, shall at all reasonable times have access to, for the purpose of examination, and the right to copy any evidence of any person being investigated or proceeded against that relates to any matter under investigation or in question. The Board, or any member thereof, shall upon application of any party to such proceedings, forthwith issue to such party subpenas requiring the attendance and testimony of witnesses or the production of any evidence in such proceeding or investigation requested in such application. Within five days after the service of a subpena on any person requiring the production of any evidence in his possession or under his control, such person may petition the Board to revoke, and the Board shall revoke, such subpena if in its opinion the evidence whose production is required does not relate to any matter under investigation, or any matter in question in such proceedings, or if in its opinion such subpena does not describe with sufficient particularity the evidence whose production is required. Any member of the Board, or any agent or agency designated by the Board for such purposes, may administer oaths and affirmations, examine witnesses, and receive evidence. Such attendance of witnesses and the production of such evidence may be required from any place in the United States or any Territory or possession thereof, at any designated place of hearing. "(2) In case of contumacy or refusal to obey a subpena issued to any person, any district court of the United States or the United States courts of any Territory or possession, or the District Court of the United States for the District of Columbia, within the jurisdiction of which the inquiry is carried on or within the jurisdiction of which said person guilty of contumacy or refusal to obey is found or resides or transacts business, upon application by the Board shall have jurisdic- tion to issue to such person an order requiring such person to appear before the Board, its member, agent, or agency, there to produce evi- dence if so ordered, or there to give testimony touching the matter under investigation or in question; and any failure to obey such order of the court may be punished by said court as a contempt thereof. "(3) No person shall be excused from attending and testifying or from producing books, records, correspondence, documents, or other evidence in obedience to the subpena of the Board, on the ground that the testimony or evidence required of him may tend to incriminate him or subject him to a penalty or forfeiture; but no individual shall be prosecuted or subjected to any penalty or forfeiture for or on account of any transaction, matter, or thing concerning which he is 150 [61 STAT.