00282nam a22001097a 4500003000400000005001700004008004100021040000800062100002000070245007300090260000900163OSt20160224095408.0160224b        xxu||||| |||| 00| 0 eng d  cN/A  aPeter Checkland  aSystems Thinking, Systems Practicebincludes a 30 year retrespective  c1999