Asymptotic Behaviour of Solutions to Hyperbolic Partial Differential   Equations
  These notes provide an introduction to and a survey on recent results about the long-time behaviour of solutions to hyperbolic partial differential equations with time-dependent coefficients. Particular emphasis is given also to questions about the sharpness of estimates.   The selection of materials is based on the mini-courses taught by the first author at the CRM, Barcelona, and by the second author at Aalto University, Helsinki, both in 2011. 
Michael Ruzhansky and Jens Wirth
math.AP