Exhibit A JOINT FILING AGREEMENTJoint Filing Agreement • March 11th, 2013 • Blackstone Holdings I L.P. • Crude petroleum & natural gas
Pursuant to and in accordance with the Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder (the “Exchange Act”) the undersigned hereby agree to the joint filing of GSO Palmetto Opportunistic Investment Partners LP, GSO Credit-A Partners LP, GSO Special Situations Fund LP, GSO Special Situations Overseas Master Fund Ltd, GSO Special Situations Overseas Fund Ltd., GSO Holdings I L.L.C., GSO Capital Partners LP, GSO Advisor Holdings L.L.C., Blackstone Holdings I L.P., Blackstone Holdings I/II GP Inc., The Blackstone Group L.P., Blackstone Group Management L.L.C., Bennett J. Goodman, J. Albert Smith III, Douglas I. Ostrover, and Stephen A. Schwarzman, on behalf of each of them of any filing required by such party under Section 13 or Section 16 of the Exchange Act or any rule or regulation thereunder (including any amendment, restatement, supplement, and/or exhibit thereto) with respect to securities of GMX Resources Inc., a Delaware corporation, and furthe
