@Misc{ 
  LorPen19,
  author = { Lorent, Andrew and Peng, Guanying },
  title = { On the Rank-$1$ convex hull of a set arising from a hyperbolic system of Lagrangian elasticity },
  journal = {  },
  year = { 2019 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4458/ },
  note = { cvgmt preprint}
}