1. NASA: Propeller propulsion. https://www.grc.nasa.gov/www/k-12/airplane/propeller.html
2. Spakovszky ZS: Archived 2012-06-28 at the Wayback Machine. 11.7.4.3 Efficiency Archived 2015-02-26 at the Wayback Machine. MIT turbines, 2002. Thermodynamics and Propulsion, main page Archived 2010-02-17 at the Wayback Machine
3. Spitfire and Merlin. https://www.quora.com/How-did-the-Spitfires-propeller-change-during-its-time-in-production?top_ans=220936742, 10 ft 9 in (3.27 m) diameter, 3 bladed de Havilland constant speed units, with narrow metal blades. Castle Bromwich with a wide bladed Rotol constant speed propeller of either 10 ft 9 in (3.28 m) diameter, with metal blades, or (on late production Spitfires) 10 ft 3 in (3.12 m) diameter, with broader, compressed wood blades.
4. Colozza, A.J.: High Altitude Propeller Design and Analysis Overview. Federal Data Systems, NASA Glenn Research Center, Cleveland, OH (1998)
5. Morgado, J., et al.: High altitude propeller design and analysis. Aerosp. Sci. Technol. 45, 398–407 (2015)