Foster care has long been a key source of both.

Its mission is to be the key source of information about the church in Chicago.

I have passed this important information on to a key source.

Tourism is now a key source of income for the area.

But the fund is still a key source of potential financing.

The area is also a key source of water for an arid region.

"We really view education as being the key source of the divide."

For this reason, they were at times a key source of intelligence.

Networks can also be a key source of information and support.

However, services are a key source of growth and employment.