Kol, J.

tinbergen policy theory development income economic order distribution model welfare cycle problem planning country market research economist business change income distribution measurement economy price labour netherland dutch continuity amsterdam study wolff production experience world nation analysis science method investment factor physics business cycles integration phenomena number trade keyne example result difference institution demand synthesis system period testing relation labour market approach bureau subject professor tinbergen university choice element interest publication unemployment professor convergence theory statistic planning bureau supply respect journal degree netherlands school capability supply side product regime