Acknowledgments

Sergey Goldin drew my attention to the role of curvature dependence in reflected wave amplitudes Goldin and Fomel (1995). I also acknowledge the support of Alexey Stovas, who introduced me to the world of DMO and collaborated with me on developing the asymptotic theory of offset continuation Stovas and Fomel (1996). Norm Bleistein suggested the Kirchhoff modeling test and collaborated with me on carrying it out Fomel et al. (1996); Fomel and Bleistein (1996). Shuki Ronen and Richard Bale pointed out to me the importance of the log-stretch domain in DMO and related problems. I appreciate the encouragement of Fabio Rocca regarding the analysis of the offset-continuation partial differential equation.