Signature - Commission Decision of 31 March 2010 amending Decision 2009/1/EC granting a derogation requested by the Republic of Bulgaria pursuant to Decision 2008/477/EC on the harmonisation of the 2 500-2 690 MHz frequency band for terrestrial systems capable of providing electronic communications services in the Community (notified under document C(2010) 1987) (Only the Bulgarian text is authentic) (2010/194/EU)