J. Park,
The wind power book. Palo Alto, CA, USA: Cheshire, 1981, p. 253 p.: ill.
R. M. C. Msengi,
Windmills within water supply, vol. no. N:o 9. Tampere, Finland: Tampere University of Technology, Dept. of Civil Engineering, 1981, p. 83 p. : 27 fig., 6 tab., loose map.