<https://secure.gravatar.com/avatar/a51124681a1cebc09add66ceb13c5e4f?s=96&amp;d=blank&amp;r=g>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.gpsworld.com/indoor-navigation-results-of-the-fccs-csric-bay-area-trials/>