<http://schema.org/description>
"The Google AdWords Blog announced they have released the call metrics, aka phone extensions to all US and Canada advertisers.   It has been in beta since 2010  and has resulted in over 5 million calls"^^<http://www.w3.org/2001/XMLSchema#string>
<https://www.seroundtable.com/adwords-call-costs-13739.html>