Two-loop sunset diagrams with three massive lines
  In this paper, we consider the two-loop sunset diagram with two different masses, m and M, at spacelike virtuality q^2 = -m^2. We find explicit representations for the master integrals and an analytic result through O(epsilon) in d=4-2epsilon space-time dimensions for the case of equal masses, m = M. 
B.A. Kniehl, A.V. Kotikov, A. Onishchenko, O. Veretin