TY - RPRT TI - Circular of the Bureau of Standards no. 583: x-ray attenuation from 10 kev to 100 Mev AU - Grodstein, Gladys White PY - 1957 PB - National Bureau of Standards CY - Gaithersburg, MD SN - NBS CIRC 583 DO - 10.6028/NBS.CIRC.583 ER -