@article{sandvik1999,
  author = {Sandvik, A. W.},
  title = {{Stochastic Series Expansion Method with Operator-Loop Update}},
  journal = {Physical Review B},
  volume = {59},
  number = {22},
  pages = {R14157--R14160},
  year = {1999},
  doi = {10.1103/PhysRevB.59.R14157}
}