Some materials are available free at Web sites like the Purdue Online Writing Lab,or OWL.

VOA: special.2010.02.11

Astronomers have recently found some surprising evidence that some of those materials may have come from comets.

VOA: special.2009.09.30

Some used natural materials like wood on the outside of the house for a pleasing appearance.

VOA: special.2009.10.27

Gone Rural also has some products available in other materials.

VOA: special.2009.05.04

"We've had past world champions that IBM has gone and employed in our Zurich research laboratory and are now working on some of the leading edge materials in science and physics.

VOA: special.2010.03.11

Most natural materials take in some sunlight.

VOA: special.2010.01.05

The new law would lift tariffs on some of the materials U.S.companies must import to make their products.

VOA: standard.2010.08.11