<https://www.guidesiena.it/#organization>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.guidesiena.it/siena-e-la-grande-guerra-e-dialoghi-tra-capolavori-in-pinacoteca/giovanni-di-paolo-la-vergine-dell-umilta>