what is the alkane of NFPA 704: Standard System for the Identification of the Hazards of Materials for Emergency Response that starts with letter "p"
SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q41581 . ?sbj wdt:P4952 wd:Q51139288 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'p')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
alkane: Q41581 nfpa 704: standard system for the identification of the hazards of materials for emergency response: Q51139288