1. Aczel, A. D., Sounderpandian, J., Saravanan, P., & Joshi, R. (2012). Complete business statistics. India: 7/e, Tata McGraw Hill Education Pvt Ltd. ISBN 13:978-0-07-107790-3.
2. Agarwal, A., Paul, V., & Das S. (2009). Forest resources: Degradation, livelihoods, and climate change, pp. 91–108 In Datt, D. and Nischal, S. (Eds.). Looking back to change track. New Delhi: TERI pp 219.
3. Barlett, J. E, I. I., Kotrlik, J. W., & Higgins, C. C. (2001). Organizational research: Determining appropriate sample size in survey research. Information Technology, Learning and Performance Journal, 19(1), 43.
4. Bhattacharya, S. C., & Salam, P. A. (2002). Low greenhouse gas biomass options for cooking in the developing countries. Biomass and Bioenergy, 22, 305–317.
5. Buysman, E. (2015). Biogas and household air quality study on household air quality and estimated health improvement of users of biogas stoves versus wood-fired stoves in rural Cambodia, Hivos people unlimited.
www.hivos.org
.