  Analytical formulas for some useful three-particles integrals are derived.
Many of these integrals include Bessel and/or trigonometric functions of one
and two interparticle (relative) coordinates $r_{32}, r_{31}$ and $r_{21}$. The
formulas obtained in such an analysis allow us to consider three-particle
integrals of more complicated functions of relative/perimetric coordinates. In
many actual problems such three-particle integrals can be found in matrix
elements of the Hamiltonian and other operators.
