References
“Principals of Macroeconomics 3e: A Revised, Online Textbook”, Is a derivative of “Principals of Macroeconomics 3e” by David Schapiro, Daniel MacDonalds and Steven A. Greenlaw used under CC BY. ” Principals of Macroeconomics 3e: A Revised, Online Textbook for Bronx Community College Students” is licensed under CC BY NC by Karen David.
References for the original OpenStax textbook can be found here.