  This paper generalises a result for upper triangular matrix rings to the
situation of upper triangular matrix DGA's. An upper triangular matrix DGA has
the form (R,S,M) where R and S are differential graded algebras and M is a
DG-left-R-right-S-bimodule. We show that under certain conditions on the
DG-module M and with the existance of a DG-R-module X, from which we can build
the derived category D(R), that there exists a derived equivalence between the
upper triangular matrix DGAs (R,S,M) and (S,M',R'), where the DG-bimodule M' is
obtained from M and X and R' is the endomorphism DGA of a K-projective
resolution of X.
