The paper of Antonio Pittelli, Alessandro Torrielli and Martin Wolf on “Secret symmetries of type IIB superstring theory on AdS_3 x S^3 x M^4” has been selected for inclusion in the Journal of Physics A Highlights of 2014 collection.  A link to the paper is here.  The complete list of J Phys A 2014 highlights can be found here.  The papers on the highlights page will be freely available throughout 2015.