@article{StulpeSinger2006,
  author    = {Werner Stulpe and Matthias Singer},
  title     = {Informational Incompleteness of the Observables Sx,Sy,Sz for Spin-1 Systems. Singer, Matthias; Stulpe, W.},
  journal   = {Foundations of Physics. 20 (1990), H. 4},
  pages     = {471 -- 472},
  year      = {2006},
}