TY - GEN AU - Petrina C. Potts C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 2014-07-01 04:07:00 DO - https://doi.org/10.6028/NIST.IR.7980-07 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 2014 TI - NIST time and frequency bulletin: ER -