TY - GEN AU - J W Cooper AU - A V Phelps AU - S J Smith C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1976-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.IR.75-944 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1976 TI - The National Measurement System for the physical properties of atoms and molecules: ER -