  Recently the Gelfand-Tsetlin construction of orthogonal bases has been
explicitly described for the spaces of k-homogeneous polynomial solutions of
the Hodge-de Rham system in the Euclidean space R^m which take values in the
space of s-vectors. In this paper, we give another construction of these bases
and, mainly, we show that the bases even form complete orthogonal Appell
systems. Moreover, we study the corresponding Taylor series expansions. As an
application, we construct quite explicitly orthogonal bases for homogeneous
solutions of an arbitrary generalized Moisil-Theodoresco system.
