  We consider the evaluation of D-dimensional conformal invariant integrals
which involve spin one-half and spin-one particles. The star-triangle relation
for the massless Yukawa theory is derived, and the longitudinal part of the
three-point Green function of massless QED is determined to the lowest order in
position space. The operator algebraic method of calculating massless Feynman
integrals is used for the evaluation.
