00341nam a2200133 a 450000500170000008200130001710000240003024500350005425000120008926000300010130000270013149000300015863000190018820251202164140.0  a339bPET  aPeterson, Willis  L  aPrinciples of economics  macro  a4th ed.  aOntariobR.D. Irwinc1980  axi, 401 p.b22 cm.bHB  aIrwin Series in economics  aMacroeconomics