EX-99.1 2 a2184647zex-99_1.txt EXHIBIT 99.1 EXHIBIT 1 --------- AGREEMENT AS TO JOINT FILING OF SCHEDULE 13G -------------------------------------------- Each of the undersigned hereby affirms that it is individually eligible to use Schedule 13G, and agrees that this Schedule 13G is filed on its behalf. Dated: April 10, 2008 AUTOMATED TRADING DESK FINANCIAL SERVICES, LLC By: /s/ Steve Keltz -------------------------------------------- Name: Steve Keltz Title: Secretary AUTOMATED TRADING DESK, LLC By: /s/ Steve Keltz -------------------------------------------- Name: Steve Keltz Title: Secretary AUTOMATED TRADING DESK HOLDINGS, INC. By: /s/ Steve Keltz -------------------------------------------- Name: Steve Keltz Title: Secretary CITIGROUP ACQUISITION LLC By: /s/ William H. Wolf -------------------------------------------- Name: William H. Wolf Title: President CITIGROUP FINANCIAL PRODUCTS INC. By: /s/ Riqueza V. Feaster -------------------------------------------- Name: Riqueza V. Feaster Title: Assistant Secretary CITIGROUP GLOBAL MARKETS HOLDINGS INC. By: /s/ Riqueza V. Feaster -------------------------------------------- Name: Riqueza V. Feaster Title: Assistant Secretary CITIGROUP INC. By: /s/ Riqueza V. Feaster -------------------------------------------- Name: Riqueza V. Feaster Title: Assistant Secretary