T.M. Ito et al., Parity-violating electron deuteron scattering and the proton's neutral weak axial vector form factor, Phys. Rev. Lett. 92, 102003 (2004)
S.P. Wells et al., Measurement of the vector analyzing
power in elastic electron proton scattering as a probe of
double photon exchange amplitudes,
Phys. Rev. C 63, 064001 (2001).