Hans nke Koster
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De Koster gara mgbatị ahụ na Leiden site na May 1927 ruo June 1933 wee tinye akwụkwọ na Mahadum Amsterdam na June 1933 majoring na Economics na-enweta akara ugo mmụta bachelor nke Economics na June 1935. De Koster rụrụ ọrụ dị ka onye isi ụlọ ọrụ maka onye nrụpụta ntụ ọka De Koster & Co na Leiden site na Eprel 1937 ruo Mee 1940. Na 10 Mee 1940 Nazi Germany wakporo Netherlands na gọọmentị gbagara London iji gbanarị ọrụ German. De Koster sonyeere ndị Dutch na-eguzogide megide ndị Germany na-arụ ọrụ ma guzobe ma duru cell Peggy na-eguzogide. Mgbe Agha Ụwa nke Abụọ gasịrị, De Koster rụrụ ọrụ dị ka onye ọrụ obodo maka ọrụ diplomatic nke Ministry of Foreign Affairs dị ka Attaché na Njikọ Mba dị na New York site na June 1945 ruo April 1946. De Koster rụkwara ọrụ ọzọ dị ka onye nduzi ụlọ ọrụ. maka onye na-emepụta ntụ ọka De Koster & Co sitere na Eprel 1946 ruo February 1967 wee bụrụ onye isi ọrụ (CEO) site na Jenụwarị 1947 ruo Septemba 1964. De Koster rụkwara ọrụ dị ka onye isi otu azụmaahịa maka ụlọ ọrụ ụlọ ọrụ na ndị ọrụ (VNO) site na Eprel. 1956 ruo February 1967 wee jee ozi dị ka osote onye isi oche nke Executive Board site na 12 March 1958 ruo 18 May 1961 na dịka onyeisi oche nke Executive Board site na 18 May 1961 ruo 12 June 1967 wee jee ozi dị ka onye òtù Social na Economic Council site na 1 April. 1958 ruo na 23 February 1967. De Koster rụkwara ọrụ dị ka onye isi oche nke Confederation of European Business site na 1 May 1962 ruo 12 June 1967.