  The experimental observables for the elastic reaction induced by protons on
electrons are calculated in the Born approximation. Model independent
expressions are derived for the differential cross section and polarization
observables. Numerical estimations are given for spin correlation coefficients,
polarization transfer coefficients and depolarization coefficients, in a wide
kinematical range. Specific attention is given to the kinematical conditions,
i.e., to the specific range of incident energy and transferred momentum.
