Complexity of solution of linear systems in rings of differential operators

Suppose given a k1×k2 system of linear equations over the Weyl algebraAn = F[X1,...X1,D4,...,Dn] or over the algebra of differential operatorsKn = F[X1,...X1,D4,...,Dn], where the degree of each coefficient of the system is less than d. It is proved that if the system is solvable overAn, orKn, respectively, then it has a solution of degree at most (k, d)20(n).