  A thorough account of electromagnetic interactions of massive neutrinos in
the theoretical formulation of low-energy elastic neutrino-electron scattering
is given. The formalism of neutrino charge, magnetic, electric, and anapole
form factors defined as matrices in the mass basis is employed under the
assumption of three-neutrino mixing. The flavor change of neutrinos traveling
from the source to the detector is taken into account and the role of the
source-detector distance is inspected. The effects of neutrino
flavor-transition millicharges and charge radii in the scattering experiments
are pointed out.
