{"source":"book","style":"apa","contributors": [{"function":"author","last":"Luhmann","first":"Niklas"} ],"pubtype": {"main": "pubnonperiodical"},"pubnonperiodical": {"title":"Introduction to systems theory","publisher":"Polity","city":"Cambridge","year":"2010"},"datasource":"/z-wcorg/","datasource":"http://www.worldcat.org","oclc":"651073942","isbn":"9780745645711 0745645712 0745645720 9780745645728"}