The Kerr Theorem, Multisheeted Twistor Spaces and Multiparticle   Kerr-Schild Solutions
  Kerr-Schild formalism is generalized by incorporation of the Kerr Theorem with polynomials of higher degrees in $Y\in CP^1.$ It leads to multisheeted twistor spaces and multiparticle solutions. 
Alexander Burinskii