smart:ClauseShape leaf node

@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix sh: <http://www.w3.org/ns/shacl#> .
@prefix smart: <https://w3id.org/standards/smart/ontologies/core/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

smart:ClauseShape a sh:NodeShape ;
    sh:property [ sh:datatype xsd:string ;
            sh:path smart:hasSectionNumber ],
        [ sh:datatype rdf:langString ;
            sh:path dcterms:title ],
        [ sh:maxCount 1 ;
            sh:minCount 1 ;
            sh:nodeKind sh:IRI ;
            sh:or ( [ sh:class smart:Clause ;
                        sh:node smart:ClauseShape ] [ sh:class smart:PublicationDocument ;
                        sh:node smart:PublicationDocumentShape ] ) ;
            sh:path dcterms:isPartOf ] ;
    sh:targetClass smart:Clause .