  The concept of QCD sum rules is extended to bound states composed of
particles with finite mass such as scalar quarks or strange quarks. It turns
out that mass corrections become important in this context. The number of
relevant corrections is analyzed in a systematic discussion of the IR- and
UV-divergencies, leading in general to a finite number of corrections. The
results are demonstrated for a system of two massless quarks and two heavy
scalar quarks.
