TY - GEN AU - G F Sushinsky AU - D G Eitzen AU - D J Chwirut AU - C J Bechtholdt AU - A W Ruff C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1976-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.IR.76-984 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1976 TI - Improved ultrasonic standard reference blocks: ER -