They have been shown to be effective for at least three years.
But he said the program may have been too effective for its own good.
Try it both ways and find out which,is more effective for you.
The changes were effective September 1, 1909 for most of the city.
It can be used just once a day and is effective for 24 hours.
It's an old system, but still the most effective for this kind of work.
However, no one knows yet whether it is effective for any of these conditions.
One style is no more effective for a situation than another.
He's the one that has to find out what's effective for him.
It can effective for every human living on the earth.