@book{4210,
	author = {Fathalla, Mahmoud F.},
	title = {A practical guide for health researchers},
	publisher = {World Health Organization Regional Office for the Eastern Mediterranean,},
	year = {2004.},
	address = {Cairo :},
	url = {https://books.google.com.pk/books?id=ktHEOwAACAAJ&dq=A+practical+guide+for+health+researchers&hl=en&sa=X&ved=2ahUKEwis3rzHv-X1AhVaP-wKHVVZDWcQ6AF6BAgKEAI}
}