Author,Title,Edition,Publisher,Year,Series,Number,ISBN,ISSN,URL "Von Foerster, Heinz and Pörksen, Bernhard and Leube, Karen",Understanding systems : conversations on epistemology and ethics,,"Kluwer Academic/Plenum Publishers,Carl-Auer-Systeme",2002,IFSR international series on systems science and engineering,,"0306467526,3896702343",,https://cir.nii.ac.jp/crid/1130000795819278720