Columbia subject headings:
Scientific apparatus and instruments--Calibration--Congresses.
Vacuum ultraviolet spectroscopy--Congresses.
X-rays--Instruments--Calibration--Congresses.
Harvard subject headings:
Scientific apparatus and instruments--Calibration--Congresses.
X-rays--Calibration--Congresses.
X-rays--Congresses
X-rays--Equipment and supplies--Congresses.
Princeton subject headings: