A priori $L^p$ estimates for solutions of Riemann-Hilbert Problems
  The authors use steepest descent ideas to obtain a priori $L^p$ estimates for solutions of Riemann-Hilbert Problems. Such estimates play a crucial role, in particular, in analyzing the long-time behavior of solutions of the perturbed nonlinear Schr\"odinger equation on the line. 
P. Deift, X. Zhou