@article{Syljuasen2002,
  author  = {O. F. Syljuåsen and A. W. Sandvik},
  title   = {Quantum {M}onte {C}arlo with directed loops},
  journal = {Phys. Rev. E},
  volume  = {66},
  pages   = {046701},
  year    = {2002},
  doi     = {10.1103/PhysRevE.66.046701},
  eprint  = {cond-mat/0202316},
}