All the content published here comes from N. Gregory Mankiw’s book – The Principles of Economics, if you wanna read the complete version, please refer to “The Principles of Economics” writen by N. Gregory Mankiw. This is really a wonderful book, really hope you buy this book. Recommend you to buy Version 6 of this book. Thanks Mankiw to share it with us. Splendid guidance book in Economic Field!!!