Columbia subject headings:
Schlieren methods (Optics)--Industrial applications--Congresses.
Schlieren methods (Optics)--Scientific applications--Congresses.
Harvard subject headings:
Optical instruments--Design and construction--Congresses
Optical materials--Congresses.
Schlieren methods (Optics)--Congresses.
Princeton subject headings:
Schlieren methods (Optics)--Congresses.