@article{StulpeGudderHagler2006,
  author    = {Werner Stulpe and S. Gudder and J. Hagler},
  title     = {An Uncertainty Relation for Joint Position-Momentum Measurements},
  journal   = {Foundations of Physics Letters. 1 (1988), H. 3},
  pages     = {287 -- 292},
  year      = {2006},
}