The De Rham-Hodge-Skrypnik theory of Delsarte transmutation operators in   multidimension and its applications. Part 1
  Spectral properties od Delsarte transmutation operators are studied, their differential geometrical and topological structure in multidimension is analyzed, the relationships with De Rham-Hodge-Skrypnik theory of generalized differential complexes is stated. 
Y.A. Prykarpatsky, A.M. Samoilenko, A. K. Prykarpatsky