This article is one of the first which says that the electric moment of ice spheroids is small and probably doesn't matter much, but that for water is large. It's useful for radar and depol. It's referenced in Austin and Bemis 1950 (which is one of the first to suggest two-polarization lidar, although they didn't use it), which in turn is referenced in Atlas et al. 1953, about scattering and atten. by non-spherical atmo particles with respect to radar.