TY - GEN AU - Kenneth L Eckerle AU - Jr Venable C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1979-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.SP.260-66 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1979 TI - Standard Reference Materials ::Didymium glass filters for calibrating the wavelength scale of spectrophotometers - SRM 2009, 2010, 2013, and 2014/ ER -