Derivation of Unified Analytic Electron Interaction Integrals over   Slater Orbitals for Diatomic Molecules
  In previous work, the necessary integrals arising from correlated wavefunctions were expressed in forms suitable for numerical integration. For the evaluation of $r_{12}$ and $1/r_{12}$ integrals an analytic formula is derived. Combinatorial aspects of more than two electron integrals are discussed. 
E.V. Rothstein
math-ph math.MP