Question: Name the  former broadcast network of the television station which is the sister stations of WGBC?
SPARQL query:
PREFIX res: <http://dbpedia.org/resource/>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT ?uri WHERE { res:WGBC prop:sisterStations ?x . ?x onto:formerBroadcastNetwork ?uri . }