TY - GEN AU - Petrina C Potts C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 2014-01-01 05:01:00 DO - https://doi.org/10.6028/NIST.IR.7980-11 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 2014 TI - NIST time and frequency bulletin: ER -