00307nam a2200085Ia 4500100002100000245003100021260000900052520014100061583001900202  aHELPMAN, Elnanan  aStructure of foreign trade  c1999  aDescribes what is known about foreign trade and in what waus ou understanding has improved as a result of the last 20 years of research.  c3/7/00kM2LMGR