Rotating incompressible perfect fluid source of the NUT metric
  A global solution of the Einstein equations is given, consisting of a perfect fluid interior and a vacuum exterior. The rigidly rotating and incompressible perfect fluid is matched along the hypersurface of vanishing pressure with the stationary part of the Taub-NUT metric. The fluid core generates a negative-mass NUT space-time. The matching procedure leaves one parameter in the global solution. 
L\'aszl\'o \'A. Gergely, Zolt\'an Perj\'es and Gyula Fodor