1. A Sharp-Focusing Schlieren System
2. A Modified Schlieren Apparatus for Large Areas of Field
3. 4Merzkirch, W., Flow Visualization, Academic Press, New York, 1974, pp.98, 99.
4. 5Boedeker, L. R. "Analysis and Construction of a Sharp Focusing Schlieren System," M.S. Thesis,Dept. of Aeronautics and Astronautics, Massachusetts Inst. of Technology, Cambridge, MA,1959.