Marie-Antoinette Tonnelat has written:

'Einstein's unified field theory' -- subject(s): Unified field theories

Louis Witten has written:

'Gravitation' -- subject(s): Gravitation, Quantum field theory, Unified field theories

which are the companies that are following the classical and neo classical theories of management????

Angelo A. Molinaro has written:

'The Two State Universe' -- subject(s): Cosmology, Gravitation, Unified field theories

Political theories are broadly classified into two categories - classical and modern. The classical theories are normative in character while the modern theories are empirical. One may further subdivide the modern theories into modern and contemporary.