  Electron scattering at large Q^2 probes a nucleon's quark core. This core's
contribution to electromagnetic form factors may be calculated using Poincare'
covariant Faddeev amplitudes combined with a nucleon-photon vertex that
automatically fulfills a Ward-Takahashi identity for on-shell nucleons. The
calculated behaviour of G_E^p(Q^2)/G_M^p(Q^2) on 2<Q^2(GeV^2)<6 agrees with
that inferred from polarisation transfer data, and exhibits a zero at
Q^2\approx 6.5 GeV^2. There is some evidence that F_2(Q^2)/F_1(Q^2) \propto
[\ln(Q^2/\Lambda^2)]^2/Q^2 for Q^2>6 GeV^2.
