F. Gronwald, METRIC-AFFINE GAUGE-THEORY OF GRAVITY .1. FUNDAMENTAL STRUCTURE AND FIELD-EQUATIONS, International journal of modern physics D, 6(3), 1997, pp. 263-303
Starting from the equivalence of reference frames, the prototype of a
gauge theory is presented and illustrated by the example of Yang-Mills
theory. Along the same lines we perform a gauging of the affine group
and establish the geometry of metric-affine gravity. The results are
put into the dynamical framework of a classical field theory. We deriv
e subcases of metric-affine gravity by restricting the affine group to
some of its subgroups. The important subcase of general relativity as
a gauge theory of translations is explained in detail.