TY - JOUR AU - M. Bradley AU - J. Porto AU - S. Rainville AU - James Thompson AU - D. Pritchard BT - Physical Review Letters DA - 1999-11 DO - 10.1103/PhysRevLett.83.4510 PY - 1999 SP - 4510 EP - 4513 T2 - Physical Review Letters TI - Penning Trap Measurements of the Masses of C133s, R87,85b, and N23a with Uncertainties <=0.2 ppb UR - http://link.aps.org/doi/10.1103/PhysRevLett.83.4510 VL - 83 SN - 0031-9007 ER -