TY - CPAPER AU - S. Chu AU - A. Mills AU - John Hall CY - Interlaken, Switzerland N1 - JILA Pub. 4416 PB - Springer-Verlag New York PP - Interlaken, Switzerland PY - 1983 SN - ISBN-13: 9783540129578 TI - Measurement of the positronium 1 Triplet S1 goes to 2 Triplet S1 two-photon transition ER -