Schematron - sgml/signature GitHub Wiki
- https://www.npmjs.com/search?q=schematron
- https://schematron.com/document/76.html?publicationid=
- https://www.mulberrytech.com/papers/schematron-Philly.pdf
- https://schematron.com/document/159.html?publicationid=
- https://www.xml.com/pub/a/2003/11/12/schematron.html
- https://www.slideshare.net/nottavy/schematron-stepbystep