... cross-sectionσarq=ρ0ρN−1k0ImSNuN−1rq(r)∂uN−1rq(r)∂nds(r), (16) 297Inverse Scattering in the Low-Frequency Region by Using Acoustic Point SourcesInverse Scattering in the Low-Frequency Region by Using Acoustic Point Sources 113.2 ... MathematicalMethods in Scattering Theory and Biomedical Engineering, Proceedings of the SeventhInternational Workshop, World Scientific Publishing Co., 2006, pp. 297–303. [16] K. Aki and P. G. Richards, ... Point-Sources and Multipoles in Inverse-Scattering Theory, Chapman and Hall/CRC, 2001.[12] J. Coyle, Locating the support of objects contained in a two-layered background medium in two dimensions, Inverse...