<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://ghk.h-cdn.co/assets/cm/15/11/480x552/54ff0472b765d-oak-leaf-lettuce-0707-xl.jpg>
<http://www.goodhousekeeping.com/food-recipes/cooking/tips/g532/types-of-lettuce/>