  The role of relativistic corrections in Coulomb scattering of heavy ions at
intermediate energy collisions ($E_{lab}\gtrsim 50$ MeV/n) is investigated by
numerically solving a full set of coupled equations. We compare two methods,
(a) one involving an exact account of interaction retardation with (b) a method
based on the expansion of effective Lagrangians in powers of the ion
velocities, $v/c$.Our study makes it possible to infer the relevance of
kinematic corrections, retardation, and magnetic interactions such as the
Darwin force. We show that analytical formulas are able to describe all aspects
of experimental interest in relativistic effects in heavy-ion Coulomb
scattering at intermediate energies without having to solve numerically the
coupled equations.
