@Article{SCI:Alt1999a,
  author =    "O. Alter and Y. Yamamoto",
  title =     "Fundamental Quantum Limit to External Force
              Detection via Monitoring a Single Harmonic
              Oscillator or Free Mass",
  journal =   "Physics Letters A",
  volume =    "236",
  number =    "4-6",
  pages =     "226--231",
  year =      "1999",
  doi =       "10.1016/S0375-9601(99)00743-4",
  url =       "http://www.sci.utah.edu/publications/alter99/Alter_PhysLettersA1999.pdf",
}