@conference{7613,
  author = {S. Chu and A. Mills and John Hall},
  title = {Measurement of the positronium 1 Triplet S1 goes to 2 Triplet S1 two-photon transition},
  year = {1983},
  publisher = {Springer-Verlag New York},
  address = {Interlaken, Switzerland},
  isbn = {ISBN-13: 9783540129578},
  note = {JILA Pub. 4416},
}