@article{ModalWorlds,
  author    = {Han{-}Hing Dang and
               Roland Gl{\"{u}}ck and
               Bernhard M{\"{o}}ller and
               Patrick Roocks and
               Andreas Zelend},
  title     = {Exploring modal worlds},
  journal   = {Journal of Logical and Algebraic Methods in Programming},
  volume    = {83},
  number    = {2},
  pages     = {135--153},
  year      = {2014},
  url       = {http://dx.doi.org/10.1016/j.jlap.2014.02.004},
  doi       = {10.1016/j.jlap.2014.02.004}
}