1. IEA. Annual Report 2006, IEA Bioenergy. IEA BIOENERGY: EXCO; 2007:01. 2006. Available from: http://www.globalbioenergy.org/uploads/media/0707_IEA_-_Bioenergy_annual_report.pdf
2. World Bank. World Development Indicators 2016 (English). World Development Indicators. Washington, D.C: World Bank Group; 2016. Available from: http://documents.worldbank.org/curated/en/805371467990952829/World- development-indicators-2016
3. WHO. WHO Natural Ventilation for Infection Control in Health-care Settings. 2009. Available from: https://www.who.int/water_sanitation_health/publications/natural_ventilation/en/ ed^eds: World Health
4. WHO. World Health Statistics. 2010. ISBN: 978 92 4 156398 7. Available from: https://www.who.int/gho/publications/world_health_statistics/EN_WHS10_Full.pdf?ua=1
5. World Health Organization. The health effects of indoor air pollution exposure in developing countries/by Nigel Bruce, Rogelio Perez-Padilla, and Rachel Albalak. 2002. World Health Organization. Available from: https://apps.who.int/iris/handle/10665/67496