"Economics can be defined in a few different ways. It’s the study of scarcity, the study of how people use resources and respond to incentives, or the study of decision-making. It often involves topics like wealth and finance, but it’s not all about money. Economics is a broad discipline that helps us understand historical trends, interpret today’s headlines, and make predictions about the coming years." (American Economics Association, What Is Economics? https://www.aeaweb.org/resources/students/what-is-economics)
Always ask your instructor what citation style should be used for research projects. See below for links to helpful resources.
Publication Manual of the American Psychological Association by 
The Bedford Handbook by 