Superfluidity of two- dimensional excitons in flat and harmonic traps
  Superfluid exciton density and superfluid transition (crossover) temperature are calculated for 2D excitons in large-size flat and harmonic traps. A generalized local density approximation for the Kosterlitz-Thouless theory is developed. 
Yu. E. Lozovik, I. L. Kurbakov, M. Willander