"Renewable energy sources Research." . . "Juvenile works" . . . . . . . "Renewable energy research" . "Renewable energy research"@en . . "Electronic books"@en . . "Presents information on the research into renewable energy sources that scientists do, including the methods that they employ and the results that they achieve." . "Presents information on the research into renewable energy sources that scientists do, including the methods that they employ and the results that they achieve."@en . . .