@book{13472,
	author = {Gamma, Erich ; Johnson, Ralph ; Vlissides, John ; Helm, Richard},
	title = {Design Patterns: Elements of Reusable Object-Oriented Software},
	publisher = {Pearson Education Inc},
	year = {,2016.},
	address = {Uttar Pradesh:},
	edition = {NA},
	note = {Includes Index}
}