Introductory resources provide background and are generally not cited as resources. A good introductory resource will explain in general terms what is currently known about your topic and help you understand the broader context of your research.
A Biographical Dictionary of Dissenting Economists by 
A Biographical Dictionary of Women Economists by 
Exemplary Economists Volume 1: North America by 
Exemplary Economists Volume 2: Europe, Asia and Australasia by 
Business Cycles and Depressions by 
Collins dictionary of economics, 4th edition
An Encyclopedia of Keynesian Economics, 2nd edition by 
An Encyclopedia of Macroeconomics by 
The Handbook of Economic Sociology, 2nd edition by 
The Penguin Dictionary of Economics by 
The Princeton Encyclopedia of the World Economy by 
