Bietenholz, W.; Bögli, Michael; Niedermayer, Ferenc; Pepe, M.; Rejón-Barrera, F. G.; Wiese, Uwe-Jens (2013). Topological lattice actions for the 2d XY model. Journal of High Energy Physics, 2013(3) Springer 10.1007/JHEP03(2013)141
