Sowa [2000] and Brachman and Levesque [2004] give an overview of knowledge representation. Davis [1990] is an accessible introduction to a wealth of knowledge representation issues in commonsense reasoning. Brachman and Levesque [1985] present many classic knowledge representation papers. See Woods [2007] for an overview of semantic networks.

For an overview of the philosophical and computational aspects of ontologies, see Smith [2003] and Sowa [2011]. For an overview of the semantic web see Antoniou and van Harmelen [2008], Berners-Lee et al. [2001], and Hendler et al. [2002]. Janowicz et al. [2015] explain the role of semantics in big data. The ontology summit (http://ontologforum.org/index.php/OntologySummit) produces an annual communique that provides a good summary of many issues in using ontologies.

The description of OWL in this chapter is based on OWL-2; see W3C OWL Working Group [2012], Hitzler et al. [2012], and Motik et al. [2012]. Krötzsch [2012] describes the OWL 2 profiles.

DBpedia [Auer et al., 2007], and YAGO [Suchanek et al., 2007; Hoffart et al., 2013; Mahdisoltani et al., 2015], Wikidata [Vrandečić and Krötzsch, 2014], (http://www.wikidata.org/) and Knowledge Vault [Gabrilovich et al., 2014] are large knowledge bases that use triples and ontologies to represent facts about millions of entities.

The top-level ontology is based on BFO, the Basic Formal Ontology, described in Grenon and Smith [2004], Smith [2015], Arp et al. [2015] and the ontology of Sowa [2000]. Other top-level ontologies include DOLCE [Gangemi et al., 2003], Cyc [Panton et al., 2006] and SUMO [Niles and Pease, 2001; Pease, 2011]. A more lightweight and widely used ontology is at http://schema.org.

SNOMED Clinical Terms (SNOMED CT) [IHTSDO, 2016] is a large medical ontology that is used in clinical practice. You can explore it at http://browser.ihtsdotools.org/.

Meta-interpreters for logic are discussed by Bowen [1985] and Kowalski [2014]. See the collection by Abramson and Rogers [1989].