TY - GEN AU - Bennett, Gwen E C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1990-01-01 05:01:00 DO - https://doi.org/10.6028/NIST.IR.90-3940-8 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1990 TI - Time & frequency bulletin No. 393: ER -