gtfs:network_id leaf node

@prefix gtfs: <http://ontology.gtfs.org/reference#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

gtfs:network_id a rdf:Property ;
    rdfs:label "network_id"@en,
        "id_red"@es,
        "id_rede"@pt ;
    rdfs:comment "Identifies a group of routes."@en,
        "Identifica un grupo de rutas."@es,
        "Identifica um grupo de rotas."@pt ;
    rdfs:domain gtfs:Route ;
    rdfs:range xsd:string .