<http://schema.org/thumbnailUrl>
<http://static.batanga.com/sites/default/files/styles/thumbnail/public/curiosidades.batanga.com/files/1024px-Bust_of_the_mathematician_John_Napier_of_Merchiston.jpg?itok=F9kjDyYU>
<http://www.batanga.com/curiosidades/2011/06/20/las-matematicas-y-la-ciencia-el-logaritmo-natural>