1. World Health Organization Global Health and Aging http://www.who.int/ageing/publications/global_health.pdf 2016
2. World Bank Group The World Bank IBRD-IDA http://data.worldbank.org/indicator 2016
3. Global, regional, and national disability-adjusted life years (DALYs) for 306 diseases and injuries and healthy life expectancy (HALE) for 188 countries, 1990-2013: quantifying the epidemiological transition;GBD 2013 DALYs and HALE Collaborators;Lancet,2015
4. Bendorf , A. World Population Trends Towards 2050 and Beyond http://www2.warwick.ac.uk/fac/soc/pais/research/researchcentres/csgr/green/foresight/demography/2010_fdi_world_population_trends_towards_2050_and_beyond.pdf 2016
5. Health benefits of Methylxanthines in cacao and chocolate;Franco;Nutrients,2013