the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Boulder, State of Colorado, on August 16, 2012.
Chief Executive Officer
constitutes and appoints Ron Squarer, R. Michael Carruthers and John R. Moore, and each or any one of
them, his true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for
him and in his name, place and stead, in any and all capacities, to sign any and all amendments (including
post-effective amendments) to this report on Form 10-K, and to file the same, with all exhibits thereto, and
other documents in connection therewith, with the Securities and Exchange Commission, granting unto
said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and
every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and
purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact
and agents, or any of them, or their or his substitutes or substitute, may lawfully do or cause to be done by
by the following persons on behalf of the registrant and in the capacities and on the dates indicated.