Ai. Davydychev et Jb. Tausk, CONNECTION BETWEEN CERTAIN MASSIVE AND MASSLESS DIAGRAMS, Physical review. D. Particles and fields, 53(12), 1996, pp. 7381-7384
A useful connection between two-loop massive vacuum integrals and one-
loop off-shell triangle diagrams with massless internal particles is e
stablished for arbitrary values of the space-time dimension it.