1. Roger C. Weatherston, Patent No. US4215977 Pulse-Free blower, (5.08.1980). USA.
2. Reduction of Noise in Roots Blower
3. John F. Weinbrecht, Patent No. US4859158 Hi-ratio recirculating gas compressor, (1.06.1989). USA.
4. John F. Weinbrecht, Patent No. US5439358 Recirculating rotary gas compressor, (8.08.1995). USA.
5. Ibraev, A. M, Vizgalov, S. V, Khisameev, I. G. 8th Int. Conf. on Compressors and their Systems (London: City University). 2013.