This resource can be used for benchmarking different RDF modelling solutions for statement-level metadata, namely: - RDF Reification, - Singleton Property, - RDF* (RDF-star). More details about this resource can be found in the following publication: Fabrizio Orlandi, Damien Graux, Declan O'Sullivan, "Benchmarking RDF Metadata Representations: Reification, Singleton Property and RDF*", 15th IEEE International Conference on Semantic Computing (ICSC), 2021. Pre-print available at: http://fabriziorlandi.net/pdf/2021/ICSC2021_REF-Benchmark.pdf The dataset contains 3 different versions of the Biomedical Knowledge Repository (BKR) knowledge graph, as described in: Vinh Nguyen, Olivier Bodenreider, Amit Sheth. "Don't Like RDF Reification? Making Statements About Statements Using Singleton Property" WWW 2014, doi: 10.1145/2566486.2567973. and, Satya S. Sahoo, Olivier Bodenreider, Pascal Hitzler, Amit Sheth and Krishnaprasad Thirunarayan. "Provenance Context Entity (PaCE): Scalable Provenance Tracking for Scientific RDF Data" in Sci Stat Database Manag. 2010; 6187: 461–470. doi: 10.1007/978-3-642-13818-8_32 The 3 knowledge graphs dumps are packaged as Gzipped RDF files in Turtle (and Turtle*) syntax. BKR-R-fullKGdump.ttl.gz for the Reification method, BKR-S-fullKGdump.ttl.gz for the Singleton method, BKR-star-fullKGdump.ttls.gz for the RDF* (RDF-star) method. The RDF REiFication Benchmark (REF) includes also a set of SPARQL (and SPARQL*) queries that can be used to compare the performance of different triplestores. Details about the SPARQL queries, and the queries themselves, are included in the "REF-Benchmark.tar.gz" archive. The queries are named after the dataset they are designed for (BKR-R or BKR-S or BKR-star), plus they include a letter identifying the query set, and a query number. E.g. the query in the file "BKR-R_F-Q3.rq" is for the BKR-R (standard reification) dataset, it is part of the query set "F" and it is the number 3 of that set "F". Hence, the same query, but translated for the RDF* dataset in SPARQL* syntax, is contained in "BKR-star_F-Q3.rq". Sets "A" and "B" are derived from the queries introduced by V. Nguyen et al. in: "Don't Like RDF Reification? Making Statements About Statements Using Singleton Property" WWW 2014, doi: 10.1145/2566486.2567973. Set "F" has been designed more with RDF* in mind as part of this benchmark (see [Orlandi et al., ICSC 2021])