Dimitri Polyakov, “New analytic solutions in string field theory: Towards a collective higher spin vacuum”, Phys. Rev. D, 90, no. 8, 2014, 086002
Julian Lee, Branko Urošević, “Perturbative calculations in the effective lagrangian and 2d closed string field theory”, Nuclear Physics B, 446, no. 1-2, 1995, 119
Dimitri Polyakov, “Solutions in bosonic string field theory and higher spin algebras in AdS”, Phys. Rev. D, 92, no. 10, 2015, 106008