A Continuum Approach to 2D-Quantum Gravity for C>1
  A Lagrangian continuum model for a string theory with central charge $c>1$ is formulated by incorporating Weyl and diffeomorphism gauge fixing. In particular the tachyon scattering amplitudes are deduced generalizing the standard $c\le 1$ computation. 
M. Martellini, M. Spreafico and K. Yoshida