Explicit construction of a Chern-Moser connection for CR manifolds of codimension two

In the present paper we suggest an explicit construction of a Cartan connection for an elliptic or hyperbolic CR manifold M of dimension six and codimension two, i.e. a pair, consisting of a principal bundle over M and of a Cartan connection form over P, satisfying the following property: the (local) CR transformations are in one to one correspondence with the (local) automorphisms for which. For any, this construction determines an explicit monomorphism of the stability subalgebra Lie (Aut(M)x) into the Lie algebra of the structure group H of P.