US car companies are to be given government help to produce more fuel efficient models.

If buying a new water heater, always buy the most efficient model possible.

On July 1, the city will replace 2,000 old buses with more efficient models.

In response, European manufacturers have developed quieter and more efficient models.

So will the potential return from replacing old equipment with newer, more efficient models.

By 1913, the company advertised it had "six efficient models in every style of body."

Should one of higher education's most efficient and effective models be left out simply because its structure is difficult to classify?

A more efficient model was the development of the hopper in 1929.

Already, 1,500 of the new, efficient models are in operation in that state.

On uniprocessor computers, however, the most efficient model has not yet been clearly determined.