Some of the results mentioned in the introduction are presented in the books [13], [15], [43], [58], [60], [68], [71], [74], [73]. Variational principles and two-sided estimates of various functionals of static fields are given in [79], [76]. Low-frequency scattering, first studied by Rayleigh (1871), is studied in [147], [151], [58], [40], [49], [50], [42], [39]. Scattering from small holes is studied in [9], [61], [25]. Potential theory for domains with smooth boundaries is given in [38]. The theory for domains with non-smooth boundaries is presented in [15], [52], and for Lipschitz domains in [22], [23], [70], [157], and in many other references. Boundary-value problems and scattering problems in domains with rough boundaries, much rougher than the Lipschitz ones, were studied in [107], [104], [31], see also [144], where the domains are of finite perimeter. In [65], [30] and [31] the embedding theorems for rough domains are given.

Reference material and an extensive bibliography on electrical capacitance can be found in [43]. There is an extensive literature on scattering by a system of many bodies and wave propagation in random media, topics outside of the scope of this book. Among many contributors to this field are [27], [59]. The effective field in random media and in media consisting of small particles has been studied in [162], [163], [26], [41], [152], [64], [159], [146], [113], to name only a few references.

In [69] there is a discussion of wave scattering by small non-spherical particles with many applications. The formulas for the...