The newspaper indicated that the leak had come from a US military source.

But even here, most funding comes from US sources.

US official sources predicted that these measures alone would reduce carbon emissions by 15 per cent.

You are denying something that even reliable US sources have admitted.

It is important to note that sometimes US based sources have not had the capacity or best economic value in these competitive bids.

It also includes all output identified as coming from U.S. official sources.

Power plants are by far the largest U.S. source of mercury air pollution.

The information was later confirmed by US sources.

Some US military sources also questioned their value.

His espionage led to the execution of a dozen U.S. sources.