As you mentioned, measuring the black market economy is not easy. Do you have any thoughts on how to include it in GDP? If GDP stands for "Gross Domestic Product", then there must be a production to be included in it. Are there any goods or services produced? If so, how should we include it? How about the volunteer work? Although this may be easier to measure in monetary terms, it may have some challenges too. In which of the complonenets of GDP would you inlude it?

Reference please