Author here. As RDF 1.2 and SPARQL 1.2 approach recommendation status, the transition from standard RDF 1.1 reification to triple terms `<<(...)>>` and edge annotations `{| ... |}` introduces some differences (e.g., asserted vs unasserted statements, named reifiers, etc.).

I put together this 4-page reference sheet covering the mental model, exact grammar constructs, and SPARQL 1.2 query idioms.

No paywall, printable A4 format. Happy to answer questions or how SPARQL 1.2 queries can be executed over local files.