“…The asymptotic formulas for diametrically small conductivity inhomogeneities and scatterers known so far form the foundation of several efficient reconstruction methods for inverse conductivity problems (see, e.g., Ammari, Moskow, and Vogelius [7], Ammari and Seo [8] or Brühl, Hanke, and Vogelius [17]) and inverse scattering problems for Maxwell's equations (see, e.g., Ammari et al [2], Iakovleva et al [33], Volkov [42], or [28,29,31,32]). In addition the general formula for electrostatic potentials from [18] has recently been used to investigate inverse conductivity problems for wires and tubes (see Beretta et al [13] or [30]).…”