1. Fans;Eck,1973
2. Mortier P. Fan or blowing apparatus. US Patent no. 507,445, 1893.
3. Anderson EL. Unit heater and ventilator. US Patent no. 1,889,588, 1932.
4. Buck CM. Blower. US Patent no. 2,033,273, 1936.
5. Present and future problems in airplane propulsion;Ackeret;Schweizer Bauzeitung,1938