(1) with the approval of the Commissioner of Housing, Parks and Recreation, promulgate, issue, amend, or rescind such rules and regulations as he deems necessary for the proper administration of this subchapter;
(2) issue such orders as he deems necessary or proper to carry out the purposes and provisions of this subchapter or to prevent the circumvention or evasion hereof;
(3) make such studies and investigations, and obtain and require the furnishing of such information under oath or affirmation or otherwise, as he deems necessary or proper, to assist him in prescribing any regulation or order under this subchapter, or in administering and enforcing this subchapter or any regulations or orders hereunder; and
(4) for such purposes, require—
(A) by subpoena or otherwise, the attendance and testimony of witnesses and the production of documents at any designated place;
(B) persons to permit the inspection and copying of documents and the inspection of housing and business accommodations; and
(C) by regulation or order, the making and keeping of records and other documents.