@article{HuebenerMariEisert2013,
  author    = {R. Huebener and Andrea Mari and Jens Eisert},
  title     = {Wick's theorem for matrix product states},
  journal   = {Physical review letters},
  volume    = {110},
  number    = {4},
  doi       = {10.1103/PhysRevLett.110.040401},
  year      = {2013},
}