The ongoing three-day 15th Karachi Literature Festival concluded today.About more than twenty sessions and nine books launching ceremonies were held.On last day a key session was held on ‘Evolving federation: two steps forward one step back’ in which renowned economist Dr Kaiser Bengali, former finance minister Asad Umar, Advocate Faisal Siddiqi and former Federal Board of Revenue chairman Shabbar Zaidiwas were panelists.