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Gang of Four

Sách về Gang of four https://www.dofactory.com/net/design-patterns https://github.com/dieforfree/edsebooks/blob/master/ebooks/Design%20Patterns%2C%20Elements%20of%20Reusable%20Object-Oriented%20Software.pdf https://cs.uwaterloo.ca/~a78khan/cs446/lectures/2011_05-may_11_DesignPatterns_01.pdf