28 | BOARD OF DIRECTORS AND OFFICERS BOARD OF DIRECTORS  » STANDING (LEFT TO RIGHT) SEATED (LEFT TO RIGHT) Our Board of Directors is responsible to our shareholders for the oversight of the company and for the imple - mentation and operation of an effective and sound corporate governance environment. We believe that effec - tive corporate governance contributes to long-term corporate performance. An effective governance structure  should reinforce a culture of corporate integrity, foster the company’s pursuit of long-term strategic goals of  growth and profit and ensure quality and continuity of corporate leadership. Our directors will continue to be  diligent in their efforts to preserve the public trust while fostering the long-term success of the company. Governance Nominated for election in June 2011 Kathleen M. Eisbrenner  $_{(3,4)}$ Founder and CEO Next Decade The Woodlands, Texas Richard K Davidson  $_{(1)}$ Retired Chairman and CEO  Union Pacific Corporation  Bonita Springs, Florida Aubrey K. McClendon  Chairman of the Board and Chief Executive Officer  Chesapeake Energy Corporation  Oklahoma City, Oklahoma V. Burns Hargis  $_{(1)}$ President  Oklahoma State University  Stillwater, Oklahoma Merrill A. “Pete” Miller, Jr.  $_{(1,2)}$ Chairman, President and CEO  National Oilwell Varco, Inc.  Houston, Texas Don Nickles  $_{(4)}$ Former U.S. Senator, Oklahoma  Founder and President  The Nickles Group, LLC  Washington, D.C. Charles T. Maxwell  $_{(3,4)}$ Senior Energy Analyst Weeden & Co. Greenwich, Connecticut Frederick B.  Whittemore  $_{(3,4)}$ Advisory Director  Morgan Stanley  New York, New York Retiring from the Board in June 2011 Frank Keating  $_{(3)}$ Former Governor, Oklahoma  President and CEO  American Bankers Association  Washington, D.C. Louis A. Simpson Chairman SQ Advisors, LLC Naples, Florida (1) Audit Committee (2) Lead Independent Director (3) Compensation Committee (4) Nominating and Corporate Governance Committee