@Misc{ 
  CarPlu18,
  author = { Carioni, Marcello and Pluda, Alessandra },
  title = { On different notions of calibrations for minimal partitions and minimal networks in $\mathbb{R}^2$ },
  journal = { Adv. Calc. Var. },
  year = { 2019 },
  doi = { 10.1515/acv-2019-0005 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3878/ },
  note = { cvgmt preprint}
}