<https://www.servicedoctors.net/heat-pumps/silver-spring-heat-pump-tip-seer-vs-hspf/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.servicedoctors.net/heat-pumps/silver-spring-heat-pump-tip-seer-vs-hspf/>