1. Renewable energy sources – an application guide;Yadav;Int. J. Energy Sci.,2013
2. Laws of flow in rough pipes;Nikuradse;VDI Forsch,1933
3. Heat transfer characteristics of a solar air heater used for drying purposes;Prasad;Appl. Energy,1983
4. Effect of artificial roughness on heat transfer and friction factor in a solar air heater;Prasad;Solar Energy,1988
5. D. Gupta, Investigations on fluid flow and heat transfer in solar air heaters with roughened absorbers, Ph.D. thesis, University of Roorkee, India, 1994.