• http://schema.org/
• http://microformats.org/
• http://json-ld.org/
• http://rdfa.info/
• http://commontag.org/
• http://opengraphprotocol.org/ ogp.me

spec.

• http://schema.org/docs/gs.html
• http://www.w3.org/TR/microdata/
• http://www.w3.org/TR/microdata-rdf/
• http://www.w3.org/TR/json-ld/
• https://html.spec.whatwg.org/multipage/microdata.html
• http://www.loc.gov/standards/datetime/

ref.

• http://historical-data.org/
• https://github.com/edsu/rdflib-microdata
• http://en.wikipedia.org/wiki/Microdata_(HTML)
• http://diveintohtml5.info/extensibility.html
• http://html5doctor.com/microdata/
• http://manu.sporny.org/2012/mythical-differences/
• https://developers.google.com/gmail/actions/getting-started - Support in Gmail
• http://www.ibm.com/developerworks/cn/web/1108_zhaifeng_microdata/

goog.

• https://support.google.com/webmasters/answer/99170?hl=en
• https://support.google.com/webmasters/answer/176035?hl=en - microdata
• https://support.google.com/webmasters/answer/146897?hl=en - microformats
• https://support.google.com/webmasters/answer/146898?hl=en - RDFa

tool

• Structured Data Testing Tool
• Open Graph Debugger
• http://rdfa.info/tools/ play