Natural gas provides the only proven low-pollution alternative to diesel, the critics say.

There has been no proven alternative, and tanks have had a relatively good track record in recent conflicts.

At a cost of more than $200,000 a year per student, it arguably makes more sense for the state to pay for live-in aides to treat children with gentler and proven alternatives at home.

Sonic soot blowers are a proven alternative to conventional steam soot blowers in power generation plants which burn a range of fossil fuels and other waste fuels including biofuels.

There is a proven alternative to counterproductive sanctions, public condemnations and arguments.

This book considers proven alternatives to imprisonment that emphasize settlement-oriented techniques over punishment, and move us towards a vision of justice as peace making rather than one of vengeance.

Nor did I suggest that she stop to consider the lack of proven and workable alternatives to our social and economic systems.

It neglects cigarettes, however, and the many who smoked for years because it was a proven alternative to eating.

The Jets activated Pat Ryan yesterday, giving them a proven alternative to Ken O'Brien at quarterback for the first time this season.

Dr. Allen J. Taylor, a cardiologist at the Walter Reed Army Medical Center, noted that patients who wanted to raise their HDL already had one proven alternative, the vitamin niacin.