A. Ernesti et G. Kopp, 2-PARTICLE PHASE-SPACE INTEGRALS FOR MULTIPARTICLE FINAL-STATES, Journal of physics. G, Nuclear and particle physics, 20(2), 1994, pp. 377-383
For the example of bremsstrahlung production, we discuss the solutions
of general two-particle phase-space integrals, which determine the cr
oss section of the production.