Black holes and gravitational waves in concert - a probe of superstring   cosmology
  Two strands of observational gravitation, one the search for astrophysical evidence of primordial black holes and the other the search for gravitational waves, may combine to provide strong evidence in favour of cosmological models based on superstring theory, the leading candidate for unifying gravity with the other fundamental forces. 
Edmund J. Copeland, Andrew R. Liddle, James E. Lidsey and David Wands