小弟跪求系统动力学始祖弗瑞斯特的经典书目的pdf版本：

• 1961. Industrial dynamics. Waltham, MA: Pegasus Communications.
• 1968. Principles of Systems, 2nd ed. Pegasus Communications.
• 1969. Urban Dynamics. Pegasus Communications.
• 1971. World Dynamics. Wright-Allen Press.

望大侠们施以援手！！！