text: De Vries obtained his PhD in 1989 from H. Daudt and H. Daalder on the article he wrote on `` Ground Politics '' ( later made into a novel by the same name ) and the educational essay `` Cabinet Crisis in the Netherlands '' .
simplified: De Vries was promoted and got his degree in 1989 from dr. H. Daudt . en dr. H. Daalder for the article he wrote on `` Ground Politics and Cabinet Crisis in the Netherlands '' .