Haunted Kaluza Universe with Four-dimensional Lorentzian Flat, Kerr, and   Taub-NUT Slices
  The duality between the original Kaluza's theory and Klein's subsequent modification is duality between slicing and threading decomposition of the five-dimensional spacetime. The field equations of the original Kaluza's theory lead to the interpretation of the four-dimensional Lorentzian Kerr and Taub--NUT solutions as resulting from static electric and magnetic charges and dipoles in the presence of ghost matter and constant dilaton, which models Newton's constant. 
Rossen I. Ivanov and Emil M. Prodanov