HTML5 RDFa and Microdata document

https://identifiers.org/pmc/PMC6961668
- http://www.w3.org/1999/02/22-rdf-syntax-ns#type
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- http://xmlns.com/foaf/0.1/page
  - http://www.ncbi.nlm.nih.gov/pubmed/PMC6961668
- http://purl.org/dc/elements/1.1/source
  - PubMed Central
- http://purl.org/dc/terms/identifier
  - PMC6961668
- http://purl.org/spar/cito/cites
  - https://identifiers.org/wikipathways/WP2572
  - https://identifiers.org/wikipathways/WP531
  - https://identifiers.org/wikipathways/WP3871
  - https://identifiers.org/wikipathways/WP1545
  - https://identifiers.org/wikipathways/WP4016
  - https://identifiers.org/wikipathways/WP3969
  - https://identifiers.org/wikipathways/WP2864
  - https://identifiers.org/wikipathways/WP3959
  - https://identifiers.org/wikipathways/WP3656
  - https://identifiers.org/wikipathways/WP2516
  - https://identifiers.org/wikipathways/WP2261
  - https://identifiers.org/wikipathways/WP45
  - https://identifiers.org/wikipathways/WP4290