<http://schema.org/headline>
"Google to let Glass owners swap out for a prescription-compatible version, invite three friends to buy Glass too"^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/google/2013/10/28/google-offers-glass-owners-option-swap-device-new-one-works-shades-prescription-frames/>