https://www.investopedia.com/terms/s/sector.asp

SECTORS × INDUSTRIES:

https://www.investopedia.com/ask/answers/05/industrysector.asp

SECTOR BREAKDOWN:

https://www.investopedia.com/terms/s/sector-breakdown.asp

11 SECTORS BY GICS:

https://www.investopedia.com/terms/g/gics.asp

https://www.fool.com/investing/stock-market/market-sectors/

https://www.bloomberg.com/markets/sectors

SECTOR ANALYSIS:

https://www.investopedia.com/terms/s/sector-analysis.asp

PUBLIC GOODS AND EXTERNALITIES:

https://gamma.app/docs/XAPFI-3Public-Goods-and-Externalities-x4vu6pr1xmms177?mode=doc

FISCAL FEDERALISM

https://gamma.app/docs/XAPFI-4Fiscal-Federalism-f1emz8kc13lmfba?mode=doc