L2 and Hp boundedness of strongly singular operators and oscillating   operators on Heisenberg groups
  In the first part, we obtain sharp results for L^2 boundedness of strongly singular operators on the Heisenberg group. We also define the oscillating convolution operators on the Heisenberg group and study their boundedness properties. In the second part, we obtain the boundedness on Hardy spaces. 
Woocheol Choi
math.FA