Reihe The Frontiers CollectionVesselin Petkov × Relativity and the Nature of Spacetime Vesselin PetkovSpringer BerlinSoftcover2011 Relativity and the Nature of Spacetime Vesselin PetkovSpringer BerlinHardcover2009 Relativity and the Nature of Spacetime Vesselin PetkovSpringer BerlineBook2009 Relativity and the Nature of Spacetime Vesselin PetkovSpringer BerlineBook2006