<https://www.phpclasses.org/blog/package/1/post/7-Showing-Google-Maps-with-many-markers-in-PHP.html>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://cobis-users.phpclasses.org/blog/package/1/post/7-Showing-Google-Maps-with-many-markers-in-PHP.html>