Non-critical string field theory for 2d quantum gravity coupled to   (p,q)--conformal fields
  We propose a non-critical string field theory for $2d$ quantum gravity coupled to ($p$,$q$) conformal fields. The Hamiltonian is described by the generators of the $W_p$ algebra, and the Schwinger-Dyson equation is equivalent to a vacuum condition imposed on the generators of $W_p$ algebra. 
J. Ambjorn (Niels Bohr Institute) and Y. Watabiki (Tokyo Institute of   Technology)