British Medical Association:

http://www.bma.org.uk/

The British Medical Association represents doctors from all branches of medicine all over the UK. It has a total membership of over 137,000, rising steadily, including more than 3,000 members overseas and over 19,000 medical student members.

World Health Organization:

http://www.who.int/en/

The World Health Organization is the United Nations specialized agency for health. It was established on 7 April 1948. WHO's objective, as set out in its Constitution, is the attainment by all peoples of the highest possible level of health. Health is defined in WHO's Constitution as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.