PREFIX : SELECT * WHERE { ?w a :Wellbore ; :name ?wellbore ; :hasWellboreInterval ?ci . ?c :extractedFrom ?ci . ?ci :hasTopDepth ?top . ?c :hasCoreSample ?s . ?s :name ?sample_name . ?top a :MeasuredDepth ; :valueInStandardUnit ?top_depth . ?well :hasWellbore ?w ; :locatedIn ?pos . ?pos :latitude ?lat ; :longitude ?long FILTER ( ( ( ( ?lat > 60 ) && ( ?lat < 62 ) ) && ( ?long > 2 ) ) && ( ?long < 3 ) ) OPTIONAL { ?s :hasPermeability ?p . ?p :valueInOriginalUnit ?permeability } }