1. Senden M. M. G. “Performance of Zigzag Air Classifiers at Low Particle Concentrations ” Eindhoven University of Technology Eindhoven The Netherlands 1978 p. 10.
2. Sweeney Patrick J. An Investigation of the Effects of Density Size and Shape Upon the Air Classification of Municipal Type Solid Waste Civil and Environmental Development Office Tyndall Air Force Base Florida June 1977 p. 20.
3. Trezak G. J. Savage G. M. and Diaz C. F. “Overview of Prepared Fuels Technology ” Proceedings of the International Conference on Prepared Fuels and Resource Recovery Technology Nashville Tenn. 1981 p. 60.
4. Worrell William A. Testing and Evaluation of Three Air Classifier Throat Designs Duke Environmental Center Duke University Durham N.C. 1977 p. 53.