Karp, Richard M. Reducibility Among Combinatorial Problems. Raymond E. Miller and James W. Thatcher (editors) (编). Complexity of Computer Computations(PDF). New York: Plenum. 1972: 85–103 [2011-07-20]. ISBN 0306307073. (原始内容(PDF)存档于2011-06-29).引用错误:带有name属性“Karp”的<ref>标签用不同内容定义了多次
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Karp, Richard M. Reducibility Among Combinatorial Problems. Raymond E. Miller and James W. Thatcher (editors) (编). Complexity of Computer Computations(PDF). New York: Plenum. 1972: 85–103 [2011-07-20]. ISBN 0306307073. (原始内容(PDF)存档于2011-06-29).引用错误:带有name属性“Karp”的<ref>标签用不同内容定义了多次