Radial geodesics as a microscopic origin of black hole entropy. III:   Exercise with the Kerr-Newman black hole
  We specify an angular motion on geodesics to reduce the problem to the case of radial motion elaborated in previous chapters. An appropriate value of entropy for a charged and rotating black hole is obtained by calculating the partition function on thermal geodesics confined under horizons. The quantum aggregation is classified in a similar way to the Reissner--Nordstrom black hole. 
V.V.Kiselev