TY - GEN AU - Goldberg, Henry C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1960-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.TN.67 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1960 TI - On the nature of the crystal field approximation: ER -