Use Business Source Complete to find articles from scholarly and trade publications.

• Search for "shadow economy" OR "underground economy"

Go to Finaeon where you will find time series of black market exchange rates for about 50 countries.

• In the lefthand column, under Series Type, use the drop-down menu to choose Exchange Rates - Black Market.

Search IZA, an independent research firm with a focus on labor markets, for articles and working papers.

• Use the Publications menu to select Discussion Papers.
• Then, perform a keyword search for shadow economy.