<http://schema.org/description>
"Symbolab is a search engine for students, mathematicians, scientists and anyone else looking for answers in the mathematical and scientific realm. Other search engines that do equation ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/insider/2012/10/08/the-guys-from-the-big-bang-theory-will-love-mathematical-search-engine-symbolab/>