Johannes de Villiers Graaff
Johannes de Villiers Graaff (also known as Jan de Van Graaff or Jannie Graaff; 19 February 1928 – 6 January 2015) was a South African neoclassical welfare economist. He was a former chairman of Nedbank.  Graaff was known for his work on optimal savings rates and contributions to the creation of the social welfare function.