<http://webisa.webdatacommons.org/84263209> <http://www.w3.org/ns/prov#wasQuotedFrom> <google.com> . <http://webisa.webdatacommons.org/84263209> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/prov#Entity> . <http://webisa.webdatacommons.org/84263209> <http://www.w3.org/ns/prov#value> "Of the compounds represented by the formula (IX), a more preferable compound is one in which both R20 and R21 are hydrogen, R22 and R23, which may be the same or different, are an alkyl group having 1 to 4 carbon atoms, or combined together to form bicyclo(3,3,1)9-nonylidene or norbornylidene, and the ring formed with Y is naphthalene which may be substituted by an alkyl group having 1 to 20 carbo" . <http://webisa.webdatacommons.org/prov/15779061> <http://www.w3.org/ns/prov#wasDerivedFrom> <http://webisa.webdatacommons.org/84263209> .