@Article{ 
  giamuc06,
  author = { Giaquinta, Mariano and Mucci, Domenico },
  title = { Graphs of $ W^{1,1}$-maps with values into $ S^1$: relaxed energies, minimal connections and lifting },
  journal = { Proc. Roy. Soc. Edinburgh Sect. A },
  year = { 2006 },
  volume = { 137 },
  number = { 5 },
  pages = { 937-962 },
  URL = { http://cvgmt.sns.it/paper/118/ },
  note = { cvgmt preprint}
}