Counting the number of master integrals for sunrise-type Feynman   diagrams via Mellin-Barnes representation
  A number of irreducible master integrals for L-loop sunrise-type and bubble Feynman diagrams with generic values of masses and external momenta are explicitly evaluated via Mellin-Barnes representation. 
Mikhail Yu. Kalmykov, Bernd A.Kniehl
hep-th hep-ph math-ph math.CA math.MP